Admissions Test Flashcards
(945 cards)
1
Q
Mixture
A
A substance made up of two or more substances not chemically bonded together.
2
Q
Abundance
A
The percentage of atoms in the universe with a particular mass.
3
Q
Alkali Metal + Chlorine =
A
Metal Chloride
4
Q
Alkali Metal + Water =
A
Metal Hydroxide + Hydrogen
5
Q
Reactivity down G1?
A
Increases
6
Q
Reactivity down G17?
A
Decreases
7
Q
Melting points down G1?
A
Decreases
8
Q
Melting points down G17?
A
Increases
9
Q
Filtration
A
Separates insoluble solids from liquids.
10
Q
Crystallisation
A
Evaporation separates soluble solids from solutions.
11
Q
Fractional Distillation
A
Separates liquids in a mixture with similar boiling points.
12
Q
Rf value
A
Distance travelled by solute / Distance travelled by solvent
13
Q
Mixtures can be separated by…
A
Physical processes
14
Q
Chlorine state at room temperature…
A
Gas
15
Q
Bromine state at room temperature…
A
Liquid
16
Q
Iodine state at room temperature…
A
Solid
17
Q
Transition elements I need to know…
A
Chromium, Manganese, Iron, Cobalt, Nickel, Copper
18
Q
What substances form ionic bonds?
A
Metals and Non-metals
19
Q
Giant Ionic Lattice
A
Huge 3D network of ions. Regular structure of positive and negative ions alternately arranged and held together by electrostatic forces of attraction.
20
Q
When can ionic compounds conduct electricity?
A
When molten or in solution (aq).
21
Q
What substances form covalent bonds?
A
Two non-metals.
22
Q
Melting points of ionic substances?
A
High
23
Q
Examples of Giant Covalent Structures…
A
Graphite, Diamond, Silicon Dioxide
24
Q
Alloying a metal makes it…
A
Less reactive and harder.
25
Nanoparticles
1-100nm, a few hundred atoms.
26
Nanotube properties
High tensile strength, electrical conductors.
27
Uses of nanoparticles...
Medical applications, sun creams, deodorant, catalysts, cosmetics, electronics.
28
Structure of fullerenes is based on...
Hexagonal rings of carbon atoms but they may also contain rings with five or seven carbon atoms.
29
First fullerene
Buckminsterfullerene (C60) which has a spherical shape.
30
Fine particles diameter?
100nm - 2500nm
31
Avogadro's number
6.022 x 10^23
32
Moles =
Mass / Mr
33
Concentration (1) =
Mass / Volume
34
Convert cm^3 into dm^3...
Divide by 1000
35
% yield =
Actual yield / Theoretical Yield x 100
36
Atom economy =
100 x Mr of desired product / Mr of all reactants
37
Concentration (2)=
Moles / Volume
38
1 mol of gas at room temperature and pressure occupies...
24 dm^3
39
Acid + Metal
Salt + Hydrogen
40
Acid + Metal hydroxide
Salt + Water
41
Acid + Metal oxide
Salt + Water
42
Acid + Metal carbonate
Salt + Carbon dioxide + Water
43
Acid + Metal Hydrogen Carbonate
Salt + Carbon dioxide + Water
44
Acidic Oxide + Base
Salt + Water
45
Acid used is HCl...
Metal Chloride
46
Acid used is H2SO4...
Metal Sulfate
47
Acid used is HN03...
Metal Nitrate
48
Mass of one mole of a substance in grams is numerically equal to...
Its Mr
49
How can metals be placed in order of reactivity?
Add the metals to water or acid and observe which ones react the most vigorously (fizzing).
50
Metals less reactive than carbon extracted by...
Reduction with carbon
51
What is removed from a compound in a reduction reaction?
Oxygen
52
How are metals more reactive than carbon extracted?
Electrolysis
53
What is an acid?
A substance with a pH less than 7, that releases hydrogen ions in a solution.
54
HCl
Hydrochloric Acid
55
HNO3
Nitric Acid
56
H2SO4
Sulfuric Acid
57
What is a base?
A substance (metal oxide, hydroxide or carbonate) that will react with an acid in neutralisation reactions.
58
H+ + OH-
H2O
59
What is a salt?
A compound formed when some or all of the hydrogen from an acid is replaced by a metal e.g. copper sulfate, copper has replaced the hydrogen from sulfuric acid.
60
Reactivity Series
Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Tin, Lead, Hydrogen, Copper, Silver, Gold, Platinum
61
When K, Na, Li and Ca react with water...
Fizzes and gives off hydrogen gas.
62
When Mg, Al, C, Zn and Fe react with water...
Reacts very slowly.
63
When tin, lead, hydrogen, copper, silver, gold and platinum react with water...
No reaction.
64
When K, Na, Li and Ca react with acid...
Explodes
65
When Mg, Al, C, Zn and Fe react with acid...
Fizzes and gives off hydrogen gas.
66
When tin and lead react with warm acid...
Reacts slowly.
67
When copper, silver, gold and platinum react with acid?
No reaction.
68
What type of reaction occurs when acids react with some metals to produce salt and hydrogen gas?
Redox Reactions
69
Soluble salts can be made from...
Acids by reacting them with solid insoluble substances such as metals, metal oxides, hydroxides or carbonates.
70
When making soluble salts how much solid do we add?
We add the solid to the acid until no more acid reacts - filter excess solid off to make a salt solution.
71
What do we do with the salt solution when making soluble salts?
Solution can be crystallised to form solid salts.
72
Strong acid - ionisation
Strong acids are completely ionised in aqueous solutions.
73
Examples of strong acids?
HCl, HNO3, H2SO4
74
Weak acid - ionisation
Weak acids are only partially ionised in aq solutions.
75
For a given concentration of acid, the stronger the acid...
The lower pH.
76
Acids are neutralised by...
Alkalis e.g. soluble metal hydroxides, and bases (e.g. insoluble metal hydroxide & metal oxides).
77
What do aqueous solutions of alkalis contain?
OH-
78
Electrolysis
Using electricity to break down a substance and extract elements from a compound.
79
Electrolyte
A liquid or solution containing ions can conduct electricity.
80
Positive electrode
Anode
81
Negative electrode
Cathode
82
Which electrode do positive ions move towards?
Cathode
83
Which electrode do negative ions move towards?
Anode
84
Metals are formed at the...
Cathode
85
Non-metals are formed at the...
Anode
86
Examples of weak acids?
Ethanoic, Citric, Carbonic acids
87
When are metals not produced at the cathode?
When the metal is more reactive than hydrogen.
88
When electrolysing metal halides, where are halogen gases produced?
At the anode.
89
What is produced at the anode when electrolysing metal sulfates?
Oxygens
90
Gains electrons at the...
Cathode
91
Loses electrons at the...
Anode
92
Electrolysis products of molten iron bromide?
Iron (s) and Bromine (l)
93
Electrolysis products of zinc oxide?
Zinc and Oxygen
94
How are metals more reactive than carbon extracted?
By electrolysis.
95
What is added to aluminium before electrolysis and why?
Cryolite - lowers the m.p. of aluminium.
96
What are the electrodes made out of during the electrolysis of aluminium?
Graphite
97
What is formed in the electrolysis of aluminium?
Aluminium at the cathode, Oxygen at the anode.
98
Products of sodium chloride electrolysis?
Chlorine gas and hydrogen gas.
99
H20 (l) =
H+ (aq) + OH- (aq)
100
Products of lead bromide electrolysis?
Lead at the cathode, Bromine at the anode.
101
When is hydrogen produced at the cathode?
If the metal is more reactive than hydrogen.
102
Exothermic Reaction
Energy transferred to the surroundings.
103
Examples of exothermic reactions...
Combustion, respiration, oxidation, neutralisation
104
Endothermic Reaction
Energy transferred from the surroundings.
105
Examples of endothermic reactions...
Thermal decomposition, citric acid & sodium hydrogen carbonate
106
Breaking bonds
Endothermic
107
Making bonds
Exothermic
108
What is the voltage produced by a cell dependent upon?
A number of factors including type of electrode and electrolyte.
109
How is a simple cell made?
By connecting two different metals in contact with an electrolyte.
110
How do rechargeable cells & batteries work?
Chemical reactions are reserved when an electrical external current is supplied.
111
What are fuel cells supplied by?
An external source of fuel e.g. hydrogen & oxygen or air.
112
What happens to the fuel in a fuel cell?
It is oxidised electrochemically within the fuel cell to produce a potential difference.
113
What do cells contain?
Chemicals which react to produce electricity.
114
In non-rechargeable cells & batteries what happens?
The chemical reactions stop when one of the reactants have been used up.
115
Are alkaline batteries rechargeable or non-rechargeable?
Non-reachargeable
116
Overall reaction in a hydrogen fuel cells?
Involves the oxidation of hydrogen to produce water.
117
What do hydrogen fuel cells offer?
A potential alternative to rechargeable cells and batteries.
118
Mean rate of reaction (1) =
Quantity of reactant used / Time taken
119
Mean rate of reaction (2) =
Quantity of product formed / Time taken
120
Factors affecting rate of reaction...
Temperature, surface area of a solid, concentration of reactants in solution, pressure of gases.
121
What do catalysts provide?
Catalysts provide an alternative route for the reaction to take place, which has a lower activation energy.
122
Le Chatelier's Principle
The idea that you change the conditions of a reversible reaction at equilibrium, the system will try & counteract the change.
123
In a reversible reaction, equilibrium moves in the direction of the exothermic reaction...
You will get a greater yield for the exothermic reaction, & a lesser yield for the endothermic reaction.
124
In a reversible reaction, increasing temperature...
Causes equilibrium to move in the endothermic direction to try to decrease it.
125
In a reversible reaction, equilibrium moves in the direction of the endothermic reaction...
You will get a greater yield in the endothermic reaction, and a lesser yield in the exothermic reaction.
126
Changing the pressure of a reversible reaction only affects an equilibrium...
Involving gases.
127
If you increase the pressure in a reversible reaction...
The equilibrium tries to reduce it - it moves in the direction when there are fewer molecules of gas.
128
If you decrease pressure in a reversible reaction...
Equilibrium tries to increase it - it moves in the direction where there are no molecules of gas.
129
Changing the concentration of either the reactants or the products in a reversible reaction means that...
The system will no longer be at equilibrium.
130
Decreasing the concentration of products in a reversible reaction...
The system tries to increase it again by reducing the amount of reactants.
131
If you decrease the temperature in a reversible reaction, the equilibrium...
Will move in the exothermic direction to transfer more thermal energy.
132
The direction of a reversible reaction can be changed by...
Changing the conditions of the reaction.
133
Equilibrium is reached when...
The forward and reverse reactions occur at exactly the same rate in apparatus which prevents the escape of reactants and products.
134
If you increase the temperature in a reversible reaction, equilibrium...
Moves in the endothermic direction to try and decrease it.
135
What does increasing the concentration of reactants in a system make?
A greater yield of products to try and decrease concentration.
136
Decreasing the concentration of products in a reversible reaction...
The system tries to increase it again by reducing the amount of reactants.
137
Crude oil
Mixture of hydrocarbons.
138
Crude oil formation
Formed over millions of years from remains of ancient biomass (mostly planktons that were buried in mud).
139
Hydrocarbonds
Compound containing atoms of carbon and hydrogen.
140
Alkane
Hydrocarbon that only has single bonds.
141
First 6 Alkanes
Methane, ethane, propane, butane, pentane, hexane.
142
General Formula for alkanes...
CnH2n+2
143
The longer the hydrocarbon chain length (bp)...
The higher its boiling point.
144
The longer the hydrocarbon chain length (v)...
The higher the viscosity.
145
The longer the hydrocarbon chain length (f)...
The lower the flammability.
146
Fractional distillation of crude oil...
Crude oil is vaporised, different molecules rise up the fractionating column and cool down, condensing at different points along the column.
147
A fuel...
A substance which when reacted with oxygen releases oxygen.
148
5 useful fuels from fractional distillation...
Petrol, diesel, kerosene, heavy fuel oil, liquefied petroleum gases.
149
Other uses of gases from fractional distillation...
Solvents, lubricants, polymers, detergents.
150
Complete Combustion
Hydrocarbon + Oxygen --> Water + Carbon Dioxide
151
Cracking...
The process of breaking down a long hydrocarbon into smaller molecules.
152
Products of cracking?
Short alkanes and alkenes.
153
Why is cracking useful?
Smaller hydrocarbons are more useful than longer ones.
154
Two types of cracking?
Catalytic and steam cracking.
155
Alkenes -->
Hydrocarbons with a double bond - C=C.
156
What are alkenes used for?
Formation of polymers.
157
Test for alkenes...
Bromine water - colour change from orange to colourless.
158
Which one out of alkenes or alkanes are more reactive?
Alkenes are more reactive than alkanes.
159
First 6 alkenes...
Ethene, propene, butene, pentene, hexene.
160
General formula for alkenes...
CnH2n
161
Are alkanes saturated of unsaturated?
Saturated
162
What is a fraction?
Hydrocarbons with similar boiling points.
163
Where are short chain hydrocarbons condensed within the fractionating column?
At the top of the column.
164
What is the crude oil heated to in the fractionating column?
350 degrees
165
Are longer or shorter hydrocarbons more or less in demand?
Shorter
166
Homologous Series
Family of organic compounds with same general formula.
167
Combustion
The reaction of a fuel with oxygen.
168
What state are alkanes at room temperature?
Gases
169
What is a fractionating column used to do?
Separate crude oil.
170
Temperature moving up the fractionating column...
Decreases
171
Incomplete combustion
Hydrocarbon + Oxygen --> Water + Carbon Monoxide + Carbon (sometimes)
172
What flame do alcohols burn with?
A blue flame.
173
How can we test for the presence of water?
White anhydrous copper (II) sulfate will turn to blue hydrate copper (II) sulfate or cobalt chloride paper will turn from blue to pink.
174
Test for carbon dioxide...
Colourless lime water becomes cloudy.
175
Methane
CH4
176
Ethane
C2H6
177
Propane
C3H8
178
Butane
C4H10
179
Pentane
C5H12
180
Hexane
C6H14
181
Hydrogenation
An addition reaction where an alkene reacts with hydrogen to form an alkane.
182
Which halogens can react with alkenes?
Fluorine, Chlorine, Bromine, Iodine
183
Ethanoic Acid + Sodium Carbonate -->
Sodium Ethanoate + Water + Carbon Dioxide
184
Ester functional group
COO
185
Alcohols react with sodium metal to produce...
Sodium alkoxide + Hydrogen gas
186
Sodium + Ethanol -->
Sodium Ethoxide + Water
187
What is produced when alcohols are burned?
Carbon dioxide + Water
188
Carboxylic Acid general formula...
CnH2n+1COOH
189
Ethanol oxidised...
Ethanol + Oxidising Agent --> Ethanoic Acid + Water
190
Example of an oxidising agent?
Potassium dichromates
191
pH of a solution of carboxylic acid...
Less than 7.
192
Butene isomers...
But-1-ene, But-2-ene
193
What gas is released when carbonates fizz in a solution of carboxylic acid?
Ester gas
194
Esters
Fragrant, volatile compounds used in flavourings and perfumes.
195
Addition polymerisation
Unsaturated monomer molecules open up their double bonds and join to form polymer chains.
196
Monomers in condensation polymerisation...
Have two functional groups.
197
Sodium carbonate + ethanoic acid -->
Sodium ethanoate + Water + Carbon dioxide
198
How many products are formed in addition polymerisation?
1 - the polymer.
199
How many products are formed in condensation polymerisation?
2 - the polymer and a small simple molecule (usually water but not always.
200
What groups do an amino acid contain?
A basic amine group and acidic carboxyl group.
201
Monomers that make up addition polymers have a...
Double carbon bond - C=C.
202
Smallest & simplest amino acid?
Glycine
203
Polymers formed from amino acids?
Polypeptides
204
Isomers of alcohol with 3 carbons...
Propan-1-ol, Propan-2-ol
205
First 6 carboxylic acid...
Methanoic Acid, Ethanoic Acid, Propanoic Acid, Butanoic Acid, Propanoic Acid, Hexanoic Acid
206
State of alcohols at room temperature?
Liquid
207
What can ethanol be formed from?
The fermentation of sugars.
208
Catalytic cracking...
Alkane heated to form vapours which are passed over a hot powdered aluminium oxide catalyst.
209
Alcohol functional group?
OH
210
Steam Cracking...
Hydrocarbon vapours mixed with steam and then heated to very high temperatures.
211
Catalytic cracking temperature...
550 degrees approx.
212
Steam cracking temperature...
800 degrees approx.
213
Are alcohols soluble in water?
Yes
214
Which type of combustion are alkenes more likely to experience?
Incomplete
215
What can alkenes undego?
Addition reactions.
216
Alkene + Hydrogen -->
Alkane
217
Alkene + Water (steam) -->
Alcohol
218
Alkene + Halogen -->
Halogenalkane
219
Functional group of alkenes...
C=C
220
Methanol
CH3OH
221
Ethanol
C2H5OH
222
Propanol
C3H7OH
223
Butanol
C4H9OH
224
Pentanol
C5H11OH
225
Hexanol
C6H13OH
226
As the length of alcohol molecules increases...
Their solubility increases.
227
pH of alcohol solution?
7
228
Alcohols are oxidised to form...
Carboxylic Acids
229
What is produced when carboxylic acids react with carbonates?
Salt, Water and Carbon Dioxide
230
Carboxylic Acid + Alcohol -->
Esters
231
What happens when carboxylic acids dissolve in water?
They produce an acidic solution but because they only partially dissociate in water, they are weak acids.
232
Ethene + Bromine -->
Dibromoethane
233
Ethanoic Acid + Sodium Carbonate -->
Sodium Ethanoate + Water + Carbon Dioxide
234
General formula for alcohols...
CnH2n+1OH
235
Methanoic Acid
CH2O2
236
Ethanoic Acid
C2H4O2
237
Propanoic Acid
C3H6O2
238
Butanoic Acid
C4H8O2
239
Pentanoic Acid
C5H10O2
240
Hexanoic Acid
C6H12O2
241
Carboxylic Acids react w/ ...
Metals to form a salt + hydrogen, react with bases to form salt and water.
242
Alcohol + Carboxylic Acid -->
Ester + Water
243
Ethanol + Ethanoic Acid -->
Ethyl Ethanoate + Water
244
Aq solutions of ethanol are produced when...
Sugar solutions are fermented using yeast.
245
Chemical Analysis
Process of establishing what chemicals are present in a substance.
246
Pure Substance
Made of a single element or compound, not mixed with any other substance.
247
How can pure and impure substances be distinguished?
By their melting & boiling points.
248
The boiling & melting points of pure substances...
Have a definite value - one specific temperature.
249
Impure substances change...
State at a range of substances.
250
Formulation
A complex mixture designed as a useful product + for a specific purpose.
251
Chromatography
A process to separate the soluble substances from a mixture e.g. dyes.
252
Stationary Phase
Paper
253
Mobile Phase
Solvent e.g. water, ethanol.
254
How many spots do pure substances form on a chromatogram?
1
255
How many spots do impure substances form on a chromatogram?
2 or more
256
What does a substance's Rf value depend on?
Solubility of the solvent - the higher the Rf value, the more soluble the substance.
257
Hydrogen Test
Lit splint will give a squeaky pop in a test tube of hydrogen.
258
Oxygen Test
Relights a glowing splint.
259
Chlorine Test
Bleaches damp litmus paper white.
260
Flame Test
A test to identify metal ions (cations).
261
Frame produced from a lithium containing compound...
Crimson
262
Frame produced from a copper containing compound...
Green
263
Frame produced from a sodium containing compound...
Yellow
264
Frame produced from a potassium containing compound...
Lilac
265
Frame produced from a calcium containing compound...
Orange-red
266
How can metal ions also be identified?
By Sodium Hydroxide
267
Which ions produce white precipitates?
Al, Mg, Ca
268
Which white precipitate dissolves in excess sodium hydroxide?
Al
269
Cu (II) ions precipitate...
Blue Precipitate
270
Fe (II) ions precipitate
Green Precipitate
271
Fe (III) ions precipitate
Brown Precipitate
272
Carbonate ion test...
Add an acid to generate carbon dioxide gas.
273
Halide ion test...
Add silver nitrate and nitric acid to generate a solid silver halide precipitate.
274
Silver Chloride colour...
White
275
Silver Bromide colour...
Cream
276
Silver Iodide colour...
Yellow
277
Sulfate ion test...
Add barium chloride and HCl - forms white precipitate.
278
Instrumental Analysis
Use of scientific technology to perform chemical analysis.
279
Instrumental Analysis is...
Accurate, Sensitive, Rapid
280
Flame emission spectroscopy...
Instrumental analysis tool for identifying metal ions.
281
Flame emission spectroscopy method...
Sample placed in flame, light emitted is passed through a spectroscope to give a spectrum which can be compared to a reference.
282
Limewater
Calcium Hydroxide
283
If a sample contains a mixture of ions...
Some flame colours can be masked.
284
Two sources of evidence for gases in the early atmosphere...
Gases in porous rocks & atmospheres on other planets.
285
Volcanoes give off which gases?
Carbon Dioxide, Nitrogen and Water Vapour.
286
Gases in trace amounts in the early atmosphere...
Methane and Ammonia.
287
Photosynthesis
Water + Carbon Dioxide --> Glucose + Oxygen
288
What gas was not present in the early atmosphere?
Oxygen
289
After algae evolved, what gas increased in the atmosphere?
Oxygen
290
What is limestone mainly made up of?
Made up of a calcium carbonate.
291
Where can carbon be locked from the atmosphere?
Fossil fuels and in sedimentary rocks.
292
Fossil Fuels
Coal, crude oil, natural gas.
293
Ammonia
NH3
294
% of Nitrogen in today's atmosphere?
78%
295
% of Oxygen in today's atmosphere?
21%
296
% of Argon in today's atmosphere?
0.9%
297
% of Carbon Dioxide in today's atmosphere?
0.04%
298
Main Greenhouse Gases
CO2, CH4, H2O vapour.
299
Example of active transport...
Uptake of nitrates into plant root cells from the soil.
300
Which molecules are dissolved in the cytoplasm, not suspended?
Salt ions and sugar molecules.
301
What happens to chemical energy from respiration before it can be utilised in movement?
Transferred / converted to Ek.
302
What is it called when water moves out of the cytoplasm of a cell?
It has been crenated.
303
What is the unit of ultrafiltration in the kidney?
The nephron.
304
What is the slowest part of the reflex arc?
Synapses.
305
When is turgor pressure created?
When plant cells fill with water - cell membrane pushed on cell wall.
306
Where are mitochondria found in sperm cells?
In the mid-section of a sperm cell.
307
What do egg cells contain to be utilised by the embryo?
Egg cells contain large amounts of food storage for the development of the embryo once fertilisation has taken place.
308
Can fats and carbohydrates be stored by the body?
Yes.
309
Where is the genetic material found in a sperm cell?
In a nucleus in the head-section of the sperm.
310
Effect of hormones?
Generalised.
311
What main molecule does not pass into the blood of healthy individuals from the kidneys?
Proteins
312
Can proteins be stored by the body?
No
313
Example of diffusion...
Urea entering the bloodstream from animal liver cells.
314
What are synapses limited by?
Rate of diffusion.
315
What is urea filtered by?
The kidneys.
316
Which molecules are suspended in the cytoplasm - NOT DISSOLVED?
Fat molecules and proteins.
317
Lithium Mass Number...
7
318
Aluminium Atomic Number...
13
319
Argon Atomic Number...
18
320
Helium Mass Number...
4
321
Lithium Atomic Number...
3
322
Oxygen Atomic Number...
8
323
Phosphorous Atomic Number
15
324
Helium Atomic Number...
2
325
Hydrogen Mass Number...
1
326
Sulfur Atomic Number...
16
327
Neon Atomic Number...
10
328
Hydrogen Atomic Number...
1
329
Silicon Atomic Number...
14
330
Boron Atomic Number...
5
331
Carbon Atomic Number...
6
332
Magnesium Atomic Number...
12
333
Caesium Atomic Number...
20
334
Potassium Atomic Number...
19
335
Beryllium Atomic Number...
4
336
Fluorine Atomic Number...
9
337
Nitrogen Atomic Number...
7
338
Sodium Atomic Number...
11
339
Chlorine Atomic Number...
17
340
Factors affecting diffusion...
Concentration gradient, temperature, surface area, diffusion distance, size.
341
What does alcohol do regarding ADH?
Alcohol suppresses ADH production, kidneys reabsorb less water so large volumes of diluted urine.
342
What is the affect of ecstasy on ADH Production?
Increases the production of ADH, so kidneys reabsorb more water, so small volumes of concentrated urine.
343
Water brought to Earth by...
Icy comets.
344
CO2 dissolved in oceans + reacted with metal oxides to form...
Metal carbonates
345
Types of shortwave radiation hitting the Earth's surface...
UV and visible light.
346
What main type of radiation is absorbed by greenhouse gases?
Infrared
347
Shortwave radiation is emitted by...
The sun.
348
Longwave radiation emitted by the...
Earth's crust
349
What percentage of sun's energy which reaches Earth is reflected...
Back into space.
350
What are the products of burning fossil fuels?
Releases carbon dioxide & water.
351
Examples of Carbon Sinks...
Rainforests and oceans.
352
What is it called when CO2 is pumped into the ground to be absorbed by porous rocks...
Carbon capture and storage.
353
What is a biofuel?
Fuel derived from plant material.
354
Biofuels are...
Carbon neutral.
355
High temperatures in an engine causes...
Nitrogen oxides to be produced.
356
What is acid rain caused by?
Nitrogen oxides & sulfur dioxide.
357
How is sulfur dioxide formed?
Formed by sulfur impurities in fossil fuels being burned.
358
Carbon dioxide is formed by the...
Complete combustion of fuel.
359
Methane + Oxygen
Carbon Dioxide + Water
360
Ammonia + Oxygen
Nitrogen + Water
361
Particulates
Cause global dimming + health problems for humans.
362
Potable Water
Water that is safe to drink.
363
Which element can be added to drinking water to sterilise it?
Chlorine
364
What else can be used to sterilise water?
Ozone (O3) and UV Light.
365
Sterilising water means to...
Kill any bacteria that may be in the water.
366
Reverse osmosis
Uses membranes to separate dissolved salts from salty water.
367
Water can be purified by...
Distillation
368
Sewage treatment involves...
The removal of organic matter and harmful microorganisms + chemicals.
369
Sewage treatment screening
Removing large solids + grit.
370
Sedimentation
Allowing large particles to settle.
371
Aerobic treatment of water...
Use microbes with oxygen.
372
Anaerobic digestion...
Breaking down sewage sludge with microbes and oxygen.
373
Smelting
Extracting metal from an ore.
374
How can we purify copper?
Electrolysis - extracted by smelting.
375
Copper can extracted from solutions of copper compounds...
By electrolysis + displacement.
376
Phytomining
Extracting metal from the ground using plants.
377
Bioleaching
Using microbes to extract metals from the ground.
378
What does LCA stand for?
Life cycle assessment.
379
Disadvantages of using distillation to purify water...
Requires large amounts of energy, expensive.
380
How can sewage sludge be treated?
By separation, broken down by digestion (anaerobic), and dried.
381
What can sewage sludge be used for?
Can be used for fertiliser as a fuel to generate electricity.
382
How is most potable water produced?
By choosing an appropriate source of fresh water, passing the water through filter beds and sterilising.
383
Why may desalination be required?
In areas where fresh water is limited.
384
How can desalination be carried out?
By distillation or reverse osmosis.
385
Disadvantage of desalination?
Large amounts of energy.
386
What things produce large amounts of waste water?
Urban lifestyles + Industrial processes.
387
What has to happen to waste water before being released into the environment?
It has to be treated.
388
Phytomining process...
Uses plants to absorb metal compounds. The plants are harvested and burned to produce ash containing metal compounds.
389
Bioleaching process...
Uses bacteria to produce leachate solutions that contain metal compounds.
390
What happens with the metal compounds produced from bioleaching and phytomining?
We can process the to extract the copper by displacement with scrap iron or electrolysis from the solutions.
391
Why are LCAs carried out?
To assess environmental impact of products in each of a number of stages.
392
1st stage of LCA...
Extracting and processing raw materials.
393
2nd stage of LCA...
Manufacturing and packaging.
394
3rd stage of LCA...
Use and operation during its lifetime.
395
4th stage of LCA...
Disposal at the end of its useful life, including transport + distribution at each stage.
396
What does paint over metal act as?
A barrier to water and oxygen.
397
What is stainless steel resistant to?
Corrosion
398
Steel coated in magnesium resistant to corrosion...
Provides sacrificial protection - Mg more reactive than Fe.
399
Metals can...
Oxidise in air.
400
Metal oxidation occurs at...
Different rates.
401
Very unreactive elements such as gold may...
Not undergo corrosion at all.
402
Corrosion
Process which happens when a metal continues to oxidise over a long period of time.
403
What does corrosion do to metals?
Weakens the metal - who metal could become a metal oxide.
404
What is rusting?
Form of corrosion - iron or steel reacts with water + oxygen.
405
Iron + Oxygen
Iron (III) Oxide
406
What colour is Iron (III) oxide?
Orange-brown
407
How can rusting be prevented easily?
Keeping water and oxygen away from iron or steel.
408
What can metals be stored in to prevent rusting?
Can be stored in an atmosphere of nitrogen or argon (inert).
409
Why can a desiccant be used to prevent rusting?
It absorbs water vapour and therefore the metal remains dry.
410
Physical barriers against rusting...
Painting, oiling & greasing, coating with plastic.
411
Electrolyte in electroplating...
Contains ions of the plating metal.
412
Electroplating
Electrolysis is used to add a thin layer of metal onto an object.
413
What is at the cathode and anode in electroplating?
Cathode - iron or steel objects, Anode - plating metal.
414
Example of object electroplated?
Steel cutlery electroplated with the use of a silver anode and silver nitrate solution.
415
Galvanisation...
Iron coated in zinc. Zinc layer prevents oxygen and water from reaching the iron.
416
Why does coating iron with zinc protect it?
Zinc is more reactive than iron - sacrificial metal.
417
Bronze...
Alloy of copper + tin.
418
Brass...
Alloy of copper + zinc.
419
Common properties of transition metals...
Able to form stable ions in different oxidation states, they often form coloured compounds, used as catalysts (as ions or atoms).
420
Steels
Alloys of iron which contain diff. amounts of carbon & additional metal elements.
421
Properties of steels are affected by...
Different compositions.
422
What does high carbon steel contain in addition to iron?
Carbon
423
High carbon steel properties?
Strong & brittle.
424
Low carbon steel properties?
Softer, more easily shaped.
425
What does stainless steel contain in addition to iron?
Chromium & nickel.
426
Stainless steel properties?
Hard, resistant to rusting.
427
Aluminium does not...
React with water.
428
Why does Al not react with water?
Protected by a natural layer of aluminium oxide.
429
What is aluminium resistant to?
Corrosion
430
Magnalium...
Aluminium + Magnesium alloy.
431
What glass is usually used?
Soda-lime
432
How is soda-lime made?
By melting silicon dioxide with sodium carbonate (limestone) - then allow the molten mixture to solidify into glass.
433
Borosilicate glass?
Another type of glass formed when silicon dioxide heated with boron trioxide.
434
Difference between borosilicate glass and soda-lime glass?
Higher b.p.
435
Clay Ceramics
Bricks, China, Porcelain
436
Forms of poly(ethene)...
Both high and low density forms.
437
LDPE
Low Density Poly(ethene)
438
LDPE properties?
Flexible, unreactive, can be made into films.
439
HDPE
High Density Poly(ethene)
440
HDPE properties?
Strong, flexible, resists shattering, resists chemical attack.
441
Thermosoftening plastics...
Melts when heated, do not have cov. bonds between neighbouring polymer molecules.
442
Thermosetting plastics...
Do not melt when heated, burns and char. Covalent bonds are strong & prevent the plastic melting when heated.
443
Composite materials...
Made up of two or more different materials which have different properties.
444
What are composite materials made up of?
Reinforcement and matrix (binds reinforcement together).
445
Fibre glass
Reinforcement - glass fibres, Matrix - polymer resin.
446
Reinforced concrete
Reinforcement - steel, Matrix - concrete.
447
Carbon Fibre reinforced polymers
Reinforcement - polymers, Matrix - polymer resin.
448
Chipboard
Reinforcement - wood chips, Matrix - resin glue.
449
How can composite materials be separated?
By physical processes.
450
Glass ceramics have...
A high melting point, stiff, brittle, poor electrical conductivity, poor thermal conductivity, poor strength, strong under compression.
451
Metals have...
High melting point, malleable good electrical conductivity, good thermal conductivity, strong.
452
Plastics have...
Usually a low melting point, usually flexible, poor electrical conductivity, poor thermal conductivity, relatively weak strength.
453
Composites have...
High m.p, stiff, brittle, poor electrical conductivity, poor thermal conductivity, strong.
454
What is ammonia?
Important industrial product used in fertilisers, explosives and dyes.
455
What is ammonia manufactured by?
The Haber Process - reversible reaction.
456
Haber Process
N2 + 3H2 -><- 2NH3
457
What can the Haber Process reach?
A dynamic equilibrium.
458
1st step of the Haber Process
N. extracted from air & H, which is obtained from natural gas, pumped through pipes.
459
2nd step of the Haber Process
Compressor, increase the mixture of gases to 200 atms.
460
3rd step of the Haber Process
Pressurised gases heated to 450 degrees, and passed through a tank, containing an iron catalyst.
461
4th step of the Haber Process
Mixture cooled so that NH3 liquefies and can be removed.
462
What happens to unreacted nitrogen and hydrogen in the Haber process?
Recycled - saves money & increases overall yield.
463
Fertilisers
Chemical formulations which contain nitrogen, phosphorus & potassium compounds to promote plant growth.
464
What are fertilisers containing the three elements - nitrogen, potassium and phosphorous?
NPK fertilisers.
465
What do fertilisers have to be?
Soluble in water.
466
Soluble nitrogen forms?
NH4- (ammonium ions), NO3- (nitrate ions).
467
Soluble phosphate forms?
PO43-
468
Ammonium nitrate...
NH4NO3 - Nitrogen = essential element.
469
Phosphate rock can react w/ nitric acid to form...
Calcium nitrate + Phosphoric acid (neutralised w/ ammonia to make ammonium phosphate).
470
Phosphate rock can react w/ sulfuric acid to form...
Single superphosphate (calcium sulfate + calcium phosphate).
471
Phosphate rock can react w/ phosphoric acid to form...
Triple Super Phosphate (calcium phosphate).
472
Ammonium Sulfate...
Salt used as a fertiliser - made by reacting ammonia solution with sulfuric acid.
473
pH of pure water...
7
474
How can the pH of water be tested?
Checked with universal indicator paper.
475
Distilled water...
Contains no dissolved solids = have a pH of 7.
476
Waste water treatment
Screened by passing through a mesh to remove solids and grits, settle in large sedimentation tanks, liquid effluent produced & a semi-solid sludge. Solid sludge taken away and digested by anaerobic bacteria.
477
When sludge is anaerobically digested...
There is the absence of oxygen, bacteria produce biogas.
478
Biogas can be...
Burned for electricity.
479
Liquid effluent contains...
A large amount of organic molecules and harmful microorganisms.
480
Aerobic digestion...
In the presence of oxygen, aerobic bacteria digest the organic molecules and harmful microorganisms.
481
After treatment what can happen to liquid effluent?
Can be safely discharged into the sea.
482
Phytomining process...
Plants grown on land containing the metal compound that we want - absorb the metal compound - concentrate it in their tissue. Harvested & burned.
483
Bioleaching process...
Mixed with low-grade ore & the bacteria carry out chemical reactions & produce a solution called a leachate - contains the metal compound we want.
484
LCAs can be...
Biased
485
What sometimes needs to happen regarding LCAS?
May need to make estimates or value judgements - not always accurate.
486
Raw materials obtained by...
Quarrying or mining.
487
Recycling metals...
Melt them and then recast them into different products.
488
Hydrogen can be produced by...
Reacting methane w/ steam.
489
Disproportionation reaction
A reaction in which the same species is simultaneously oxidised and reduced.
490
Oxidation state
Represents the total number of electrons that the element has either accepted by an element or removed from an element to get to its current form.
491
Positive Oxidation State
Shows the total number of electrons which have been removed from an element to get to its present state.
492
Negative Oxidation State
Shows the total number of electrons added to an element to get to its present state.
493
Oxidation
Involves an increase in oxidation state.
494
Reduction
Involves a decrease in oxidation state.
495
An oxidising agent...
Is normally a non-metal or positive ion, cause oxidation reactions to take place & gains electrons from other atoms or ions (is itself reduced).
496
A reducing agent...
Is usually a metal or negative ion, donates electrons to another element or ion (reducing the other species), is itself oxidised.
497
Redox Reaction
One in which both oxidation & reduction takes place.
498
Example of a redox reaction?
Displacement reactions.
499
Carbonate ion
CO32-
500
Examples of small covalently bonded molecules...
Water, ammonia, methane.
501
Metals exist as...
A giant structure of positively charged ions surrounded by delocalised electrons.
502
What forces can exist between molecules?
Intermolecular forces
503
What do intermolecular forces need to be overcome in?
Melting & Boiling
504
pH is a measure of...
A measure of hydrogen ion concentration.
505
A change of 1 on the pH scale corresponds to...
A change by a factor of 10 in H+ ion concentration.
506
Monoprotic acids?
Can only donate one proton.
507
Examples of monoprotic acids?
HCl, CH3COOH (acetic acid), HNO3
508
Polyprotic acid
Can donate two or more protons.
509
Examples of polyprotic acids...
H2SO4, H3PO4 (phosphoric acid), C10H16N2O8 (ethylenediaminetetraacetic acid)
510
Diprotic acids
Can donate two protons e.g. H2SO4.
511
Triprotic Acids
Can donate three protons e.g. H3PO4
512
Catalysts do not...
Affect the position of equilibrium.
513
Catalysts are...
Not used up in a reaction & are chemically unchanged at the end of a reaction.
514
In an exothermic reaction...
Delta H is negative - negative enthalpy change.
515
In an endothermic reaction...
Delta H is positive - positive enthalpy change.
516
If a reversible reaction is exothermic in one direction...
It is endothermic in the other direction.
517
Direct current...
Used in electrolysis to maintain a consistent, one-way flow of electrons.
518
Polyamides
Polymers where the repeating units are held together by amide links.
519
Formula of an amide group?
CONH2
520
The biodegradability of polymers depends on...
The types of intermolecular forces within the polymer chains.
521
Biodegradable polymers...
Are broken down by natural processes such as decomposition.
522
Non-biodegradable polymers...
Can take hundreds of years to break down and can have long-term environmental impacts.
523
The reactivity of a metal is linked to its...
Tendency to form positive ions & the ease of extraction of the metal.
524
Fluoridation
The addition of small amounts of fluoride to drinking water to prevent tooth decay.
525
Selective Breeding steps
1 - Choose parent w/ desired characteristics.
2 - Breed them together.
3 - Choose best offspring.
4 - Continue over many generations.
526
Purpose of Selective Breeding...
Desirable characteristics.
527
2 reasons for Selective Breeding?
Produce food crops, produce domesticated animals.
528
Selectively breed for...
- Disease resistance (food crops).
- More milk/meat (animals).
- Gentle nature (domestic animals).
- Unusual / large flowers.
529
Disadvantage of selective breeding in animals?
Inbreeding - health issues.
530
Disadvantage of selective breeding in plants?
Crops - very similar DNA - genetic disease can kill all plants.
531
What part of the brain controls unconscious activities i.e. heart rate and breathing rate.
Medulla Oblongata
532
What part of the brain controls intelligence, personality, conscious thought and high-level functions e.g. language and verbal memory?
Cerebrum
533
What part of the brain controls balance, coordination of movement and muscle activity?
Cerebellum
534
Accommodation
The process of changing the shape of the lens to focus on near or distant objects.
535
What lens can be used to treat hyperopia?
Convex spectacle lenses.
536
What lens can be used to treat myopia?
Concave spectacle lenses.
537
Other eye treatments...
Contact lenses, laser eye surgery, replacement lenses.
538
Myopia
Short-sightedness: when distant objects appear blurred, therefore rays of light focus in front of the retina.
539
Hyperopia
Long-sightedness: when near object looks blurred because rays of light focus behind the retina.
540
Reasons for hyperopia...
Eyeball too short - distance between lens and retina is too small; a loss of elasticity of the lens - cannot become thick enough to focus - often age-related.
541
What happens to the pupil in bright light?
Radial muscles relax, circular muscles contract, contracted pupil = smaller.
542
Reasons for myopia...
Eyeball being too long/elongated, distance between lens and retina = too great; lens beings too thick and curved - light focused in front of the retina.
543
Suspensory Ligament
Tightens and slackens to control the shape of the lens.
544
Sclera
Tough, white outer-layer of the eye. Helps protect eye from injury.
545
What happens to the pupil in dim light?
Radial muscles contract, circular muscles relax, pupil becomes dilated.
546
How does the eye focus on near objects?
Ciliary muscles contract, suspensory ligaments slacken, so lens is thick and more curved (refracts light rays more strongly).
547
How does the eye focus on distant objects?
Ciliary muscles relax, suspensory ligaments pulled tight, lens is thinner and flatter - only refracts light rays slightly.
548
Where is the cell body found on the sensory neurone?
Along/on the neurone fibre.
549
Where is the cell body found on the motor neurone?
Beginnings of the neurone fibre.
550
Hormones used in IVF?
FSH, LH
551
FSH inhibits...
Oestrogen
552
Oestrogen stimulates...
LH
553
Where is progesterone produced?
Corpus luteum
554
Hormones produced in the pituitary gland?
LH + FSH + ADH
555
Where are auxins produced?
Meristems
556
Where is ethene gas produced in plants?
Gas produced by ageing parts of the plant.
557
Gibberellin
Stimulates seed germination, stem growth and flowering.
558
Ethene
Influences the growth of the plant by controlling cell division - also stimulates enzymes that cause fruit to ripen.
559
Auxins
Control the growth of a plant in response to light - phototropisms & gravitropisms/geotropisms.
560
Progesterone
Maintains uterus lining.
561
Progesterone inhibits...
FSH & LH
562
FSH
Egg development and maturation.
563
LH
Ovulation
564
Oestrogen
Causes uterus lining to rebuild.
565
If the motor area is stimulated during electrical stimulation, the patient is...
Making involuntary movement.
566
Using electrical stimulation...
Scientists stimulate different parts of the brain with a weak electric current and ask patients to describe what they experienced.
567
MRI
Brain imaging technique - magnetic resonance imaging.
568
EEGs
Created and studied to observe the electrical activity of the brain.
569
If the visual area is stimulated by electrical stimulation, the patient may...
See a flash of colour.
570
The brain controls...
Complex behaviour.
571
How to MRIs work?
Use strong magnetic fields and radio waves to show details of brain structure and function.
572
Levels of organisation...
Cells - tissues - organs - organ systems.
573
Role of mitosis in...
Growth by increasing cell numbers, repair of tissues, replacement of worn out cells, and asexual reproduction.
574
Role of meiosis in...
Reducing the chromosome number.
575
Full chromosome complement restored in...
Fertilisation
576
Asexual reproduction involves...
Two parents and offspring are genetically identical when no mutations occur.
577
Sexual reproduction involves...
Two parents, offspring are genetically different in relation to each other and the parents - leading to increased variation.
578
Iris reflex
Controls the size of your pupil.
579
Optic Nerve
Carries impulse between the brain and eye.
580
Cells found in the retina...
Rod & Cone cells.
581
How many rod cells are approximately in the retina?
120 million
582
What is the pancreas?
A coordination centre
583
CNS
Brain + Spinal Cord
584
Oestrogen inhibits...
FSH release.
585
Oestrogen stimulates...
Luteinising hormone
586
What hormones can be found in contraceptive pills?
Oestrogen and progesterone.
587
What hormones are issues as fertility drugs?
FSH & LH
588
Disadvantages of IVF treatment...
Emotional & physically stressful, success rates are not high, can lead to multiple births - putting both the babies and mother at risk.
589
The endocrine system...
Is composed of glands which secrete chemicals called hormones directly into the bloodstream.
590
What happens to the amino acids in the liver?
Deaminated to form ammonia.
591
What happens to ammonia in the blood?
Ammonia is toxic so it is immediately converted to urea for safe excretion.
592
What hormone controls water levels?
ADH
593
Where is ADH released from?
Pituitary gland
594
What does ADH cause?
More water to be reabsorbed back into the blood from the kidney tubules as a result of increased permeability.
595
How are thyroxine levels controlled?
By negative feedback.
596
After auxins are produced...
They move backwards to stimulate cell elongation (enlargement) process which occurs in the cells just behind the tips.
597
Extra auxin promotes...
Growth in the shoot but inhibits growth in the root.
598
When a shoot tip is exposed to light...
More auxin is accumulated on the side that is in the shade than the side that is in the light.
599
What does the accumulation of auxins on the shade cause?
Cells to grow faster on the shaded side, to the shoot bends towards the light.
600
When a shoot is growing sideways...
Gravity produces an unequal distribution of auxin in the tip, with more auxin on the lower side.
601
When more auxin is concentrated on the lower side of the shoot, what happens?
The lower side grows faster, so the shoot bends upwards.
602
Excess ______ are removed via the kidneys in the urine?
Water, ions and urea are removed via the kidneys in the urine.
603
3 uses of auxins?
Killing weeds, growing from cuttings with rooting powder, growing cells in tissue culture.
604
How can auxins be used to kill weeds?
Most weeds are broad-leaved, which are the type of plants that auxins affect. Auxins disrupt their normal growth patterns, which kills them.
605
What happens when we grow cuttings using rooting powder containing auxins?
They will produce roots rapidly and start growing new plants, allowing growers to produce clones on plants quickly.
606
What drugs may need to be taken with a mechanical valve?
Anticlotting drugs.
607
A biological heart transplant may...
Be rejected from the body.
608
To reduce the chance of a heart being rejected, what drugs can be taken?
Immunosuppressants.
609
Which individuals cannot take statins?
People with liver disease or people who are pregnant or breastfeeding.
610
Tissue
Group of cells with similar structures working together for a specific function.
611
Amylase is produced in...
Salivary gland & pancreas.
612
Proteases are produced in...
Stomach, pancreas, small intestine.
613
Lipases are produced in...
Pancreas & small intestine.
614
Function of bile?
Emulsifies fats & neutralises food from stomach.
615
Risks of food tests?
Ethanol is flammable, Biuret is corrosive.
616
Differentiation
Process where a cell becomes specialised/adapted to perform specific functions.
617
Stem Cell
Undifferentiated cell with the potential to become specialised.
618
Cloning
Production of an identical offspring by asexual reproduction/mitosis.
619
Which diseases can be treated with stem cell treatment?
Paralysis, diabetes, blindness.
620
Therapeutic Cloning
An embryo is produced with the same genes as the patient.
621
How can stem cells be used in regards to plants?
Rare species can be cloned to protect from extinction, crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers.
622
Measles can be spread...
By droplet infection.
623
HIV can be spread...
By sexual contact - exchange of bodily fluids (shared needles, blood transfusions).
624
What does a plant infected by TMV look like?
Mosaic pattern of discolouration on leaves.
625
What does TMV cause?
Destroys chloroplasts, so decreases photosythesis.
626
Name 2 bacterial diseases?
Salmonella, gonorrhoea.
627
Salmonella bacteria can be found in...
Raw meat, chicken, eggs.
628
Symptoms of salmonella?
Fever, abdominal cramps, diarrhoea, vomiting.
629
Symptoms of gonorrhoea?
Yellow/green discharge from penis/vagina, pain on urination.
630
Long-term effects of gonorrhoea?
Long-term pelvic pain, infertility, ectopic pregnancies.
631
Name a fungal disease in humans?
Athlete's foot.
632
Name a fungal disease in plants?
Rose Black Spot
633
Malaria spread by...
Female anopheles mosquitoes
634
Malaria damages...
Blood & liver cells.
635
Symptoms of malaria?
Fevers and shaking.
636
How is rose black spot spread?
Carried on the wind or water.
637
Symptoms of measles?
Fever and red skin rash.
638
What does rose black spot look like?
Purple or black spots develop on leaves, which often turn yellow and drop early.
639
Plasma
A component of blood - yellow liquid which carries blood cells, proteins and dissolved substance around the body.
640
Platelets function?
Blood clotting.
641
Arteries (compared to veins)...
Thicker walls, more elastic tissue, no valves.
642
Veins (compared to veins)...
Thinner walls, less elastic tissues, have valves.
643
Blood flowing in arteries...
Oxygenated (generally), more nutrients, less wastes.
644
Blood flowing in veins...
Deoxygenated, less nutrients, more wastes.
645
Double circulatory system.
One part carries blood between the heart and lungs - the other carries blood between the heart and the rest of the body.
646
Left side of the heart...
Is thicker.
647
Method to unblock a coronary artery...
Stent
648
Statins reduce...
Blood cholesterol levels.
649
What valves are used to replace a damaged heart valve?
Mechanical or biological valves.
650
Natural Pacemaker...
A group of cells in the right atrium that controls the resting heart rate.
651
Artificial Pacemaker...
Sends strong, regular electrical signals to the heart to stimulate it to contract properly.
652
What do artificial hearts do?
Can be used as a temporary treatment while waiting for a heart transplant.
653
Ribcage...
Protects the heart & lungs.
654
What is the name of the tissue that covers and protects the surface surface of plants?
Epidermal Tissue
655
Xylem and phloem are organised...
In bundles, with xylem on the inside and phloem on the outside - the vein.
656
Potometer used to...
Stimulate transpiration rate.
657
Organs
Aggregations of tissues performing specific functions.
658
Coronary heart disease?
Layers of fatty material builds up inside the coronary arteries, narrowing them.
659
The build up of fatty deposits in the coronary arteries reduces...
The flow of blood through the coronary arteries, resulting in a lack of oxygen for heart muscle.
660
Stents used to...
Keep the coronary arteries open.
661
Heart valves may become faulty in some people, preventing...
The valve from opening fully, or the heart valve might develop a leak.
662
In the case of heart failure...
A donor heart or heart & lungs can be transplanted.
663
Risks of cardiovascular disease?
Diet, smoking and lack of exercise.
664
Examples of cardiovascular disease?
Coronary heart disease, heart attacks, heart failure, faulty valves.
665
Benefits of stents...
Relatively quick surgery, effective for a long time, blood can flow naturally.
666
Issues with stents...
Requires surgery, the patient could later develop a blood clot near the stent; a thrombosis, does not treat the cause of the issue.
667
Statins alter...
The balance of cholesterol in the bloodstream, increasing the good cholesterol (HDL) and decreasing the bad cholesterol (LDL).
668
Cholesterol is...
A type of lipid.
669
Benefits of statins?
Ensures that blood can keep flowing, increase the vol. of good cholesterol (HDL), but decrease the vol. of bad cholesterol (LDL), lowers the risk of coronary heart disease and other cardiovascular diseases.
670
Issues with statins?
Need to be taken regularly, can also cause side effects such as headaches, such as headaches, kidney failure & liver problems.
671
Heart valves may become faulty due to...
Age, heart attacks & infections.
672
Biological valves...
Come from another human, a pig, or a cow.
673
Which type of valves last longer?
Mechanical valves.
674
Homozygous
The individual has two alleles for this gene.
675
Heterozygous
The individual has two different alleles for this gene.
676
Genotype
The genetic makeup of an organism for a particular gene.
677
Phenotype
The displayed characteristic due to the interactions between alleles.
678
Female genotype
XX
679
Male genotype
XY
680
Polydactyly
Genetic condition causing the individual to have extra fingers or toes.
681
Is polydactyly recessive or dominant?
Dominant condition - PP or Pp (homozygous dominant or heterozygous).
682
Is cystic fibrosis dominant or recessive?
Recessive - cc (homozygous recessive), would result on cystic fibrosis.
683
Methods for screening embryos?
Amniocentesis, chorionic villus sampling, IVF
684
Concerns of screening embryos?
Causing miscarriage, ethical concerns, inaccurate results, expensive.
685
Benefits of screening embryos?
Know if your child will have a disorder, able to decide if to proceed with a pregnancy or abortion.
686
Is Huntington's dominant or recessive?
Dominant
687
2 gametes in flowering plants?
Pollen and egg cells.
688
Recessive
The individual needs two copies of their alleles for its phenotype to be seen.
689
What do injections/implants/skin patches release?
Slowly releases progesterone to inhibit the maturation & release of eggs for a number of months or years.
690
What do barrier contraceptive methods do?
Prevent the sperm from reaching the egg.
691
Intrauterine devices...
Prevent the implantation of an embryo or releases hormones.
692
Dominant
The individual only needs one copy of this allele for its phenotype to be seen.
693
Auxins used in growing cells in tissue culture...
Auxins are added to the growth medium, along with nutrients, to stimulate the cells to divide to form both roots & shoots.
694
When a shoot tip is exposed to light...
More auxin accumulated on the side that is in the shade compared to the side that is in the light.
695
Gibberellin used to control dormancy?
Seeds can be treated with gibberellin to alter dormancy & make them germinate @ times of the year they wouldn't normally. Can also ensure all seeds in a batch germinate at the same time.
696
Gibberellins used to induce flowering?
Some plants require certain conditions to flower i.e. longer days, low temperatures. Gibberellins allows plants to flower without a change in their environment, or to grow bigger flowers.
697
Gibberellins used regarding fruits?
Seedless fruits do not grow as large as seeded fruits, but if gibberellins are added to these fruits, they will grow larger to match the size of the normal varieties.
698
Ethene influences...
The growth of plants by controlling cell division. It also stimulates enzymes that causes fruit to ripen.
699
Ethene's use commercially...
It can be used to speed up the ripening of fruits either when they are still on the plants or during transport to shops.
700
Disadvantages of dialysis?
Carefully controlled diet / long periods connected to a machine (poor quality of life as immobile when connected).
701
Concentration of urea in the dialysis fluid...
Zero/none.
702
2 treatments for kidney failure?
Dialysis and kidney transplant.
703
Muscle adaptations?
Special proteins for concentration, many mitochondria for energy, store glycogen to release glucose for respiration.
704
What cells keep the phloem alive?
Companion cells
705
Surgical contraceptive methods...
Female + Male sterilisation.
706
Genetic Engineering
1 - Select desired characteristic.
2 - Isolate gene w/ restriction enzymes.
3 - Insert gene into vector - joined by a ligase enzyme.
4 - Replicate
707
GM crops include...
Crops that are resistant to insect attack or to herbicides. Generally show increased yields.
708
Concerns of GM crops?
The effect on populations of wild flowers & insects, the effects of eating GM crops on human health have not been fully explored.
709
Genetic Engineering
Modifying the genome of an organism to give a desired characteristic.
710
Tissue Culture
Using small groups of cells from part of a plant to grow identical new plants.
711
What is tissue culture important for?
Preserving rare plant species or commercially in nurseries.
712
Cuttings
Produce many identical plants from a parent plant.
713
Embryo transplants
Splitting apart cells from a developing animal embryo before the become specialised, then transplanting the identical embryos into host mothers.
714
2 examples of genetic engineering in practice...
Bacterial cells engineered to produce insulin, plant crops engineered to be resistant to disease / have bigger & better fruits.
715
Fossils may be formed from...
Hard parts of animals not decaying properly, conditions didn't allow decay, minerals replaced parts of the organisms it decayed, traces (e.g. footprints) preserved.
716
Why is the fossil record incomplete?
Soft bodies of early animals decayed easily, geological activities destroyed fossils.
717
Extinction can be caused by...
New predators, new diseases, one species outcompeting another.
718
Example of a disease resistant to antibiotics?
MRSA
719
Antibiotics should not be...
Prescribed inappropriately e.g. should not be prescribed for viral infections.
720
People should complete...
Their course of antibiotics.
721
Agricultural use of antibiotics is...
Restricted
722
3 types of adaptations?
Structural, behavioural, functional.
723
Animals may compete for...
Water, mates, territory, food.
724
Plants may compete for...
Nutrients, water, space, light.
725
Abiotic factors
Light intensity, temperature, moisture, soil pH, wind intensity, carbon dioxide levels, oxygen levels.
726
Biotic factors
Food availability, new predators, new pathogens, species outcompeting.
727
Percentage of biomass transferred from one trophic level to another?
0.1%
728
Biomass is lost from the food chain because...
Not all of the material is eaten e.g. bones + teeth, energy lost as faeces.
729
Extremophile
Organism that survives and reproduces in the most difficult conditions.
730
Functional adaptations?
Internal adaptations, can be related to processes such as reproduction and metabolism.
731
Extremophiles can live in...
Very high concentrations of salt.
732
Examples of extreme environments?
Very high temperatures, pressure or salt concentration.
733
Stable Community
One where all the species and environmental factors are in balance, so that population sizes remain constant.
734
Aerobic respiration
Exothermic reaction that breaks down glucose to release energy using oxygen.
735
Aerobic respiration equation?
Glucose + Oxygen --> Carbon Dioxide + Water
736
Oxygen debt
Amount of oxygen needed to break down lactic acid.
737
What do plants produce in anaerobic respiration?
Plants produce ethanol and carbon dioxide.
738
Functions of the liver?
Detoxification, breakdown of old blood cells, remove lactic acid (convert to glucose).
739
Fermentation
Glucose --> Ethanol + Carbon Dioxide
740
Anaerobic respiration equation
Glucose --> Lactic Acid
741
Photosynthesis has...
Endothermic
742
Correlation
A link between 2.
743
Causation
One thing leads to another.
744
Risk factors for developing cancer...
Smoking, obesity, common viruses, UV exposure, genetic factors.
745
Mothers drinking alcohol during pregnancy can cause...
Fetal alcohol syndrome.
746
Long-term heavy drinking can lead to...
Liver cirrhosis, liver cancer & brain damage.
747
Carcinogen in cigarette smoke...
Tar
748
Tobacco smoke & cardiovascular diseases...
Increased heart rate, damage artery lining, increase risk of clot formation, increase blood pressure.
749
Smoking effect on fetuses...
Premature birth, low birthweight, still birth.
750
High fat diet leads to...
Fat deposits in coronary arteries.
751
Spread of malaria can be stopped by...
Using mosquito nets, using insecticides, removing standing water, take antimalarial drugs.
752
Nitrate ions in plants...
Make proteins.
753
Magnesium ions in plants...
Make chlorophyll for photosynthesis.
754
Symptom of magnesium deficiency in plants?
Antibacterial chemicals/poisons.
755
Physical adaptations in plants to defend against herbivores?
Thorns/hairy stems & leaves/dropping or curling/mimicry.
756
Physical barriers against pathogens (plants)...
Cellulose cell wall / tough-waxy cuticle / bark on trees / leaves fall.
757
Digitalis originates from...
Foxgloves
758
Aspirin originates from...
Willow Trees
759
What is used in preclinical testing?
Cells, tissues and live animals used in preclinical testing.
760
Double-blind trial?
Neither the doctors nor the patients know who gets the real drug / placebo.
761
Stage 1 of Drug Development
Preclinical testing
762
Stage 2 of Drug Development
Phase 1 clinical trials - Low doses tested on a few healthy individuals to check for side-effects.
763
Stage 3 of Drug Development
Phase 2 clinical trials - Low doses tested on a few healthy individuals to check for side-effects.
764
Stage 4 of Drug Development
Phase 3 clinical trials - Large number of people are tested to check that the drug works.
765
Producing mAbs...
Inject mouse w/ a pathogen, combining B-lymphocytes w/ tumour cells - creates a hybridoma cell, placed in a petri dish to produce lots of antibodies.
766
Hybridoma cells can produce...
Lots of antibodies and still divide rapidly by mitosis.
767
Microorganism that produces penicillin...
Penicillium
768
What are drugs tested for?
Toxicity, efficacy and dose.
769
To reduce the risk of measles...
Most young children are vaccinated against measles.
770
HIV can be controlled with...
Antiretroviral drugs
771
Treatment for gonorrhoea
Antibiotics.
772
Treating rose black spot...
Can be treated using fungicides and/or removing and destroying the affected leaves.
773
To restrict the spread of malaria, we can prevent...
Mosquitoes from breeding together.
774
How can plant diseases be detected?
Stunted growth, spots on leaves, areas of decay (rot), growths, malformed stems or leaves, discolouration, the presence of pets.
775
Can identify plant diseases by..
Referencing a gardening manual or website, taking infected plants to a laboratory to identify the pathogen, using testing kits that contain mAbs.
776
Stunted growth in plants can be caused by...
A nitrate deficiency.
777
Chlorosis can be caused by...
A magnesium deficiency.
778
Health
A state of physical and mental wellbeing.
779
Factors that affect health?
Diet / Stress / Life situations (e.g. hygiene) / pathogens / immune system.
780
Pathogens spread by...
Air/droplet infection, direct contact, water.
781
Methods to prevent the spread of disease?
Isolation, maintain good hygiene, destroy vectors, vaccination.
782
TMV virus spread by...
Direct contact/vectors.
783
3 Viral diseases
Measles, HIV/AIDS, TMV.
784
Measles
Can lead to blindness & brain damage.
785
Most phenotypic features are...
The result of multiple genes rather than a single gene inheritance.
786
Chromosomes contain...
DNA
787
Protein synthesis involves the production...
Of proteins from amino acids.
788
Genetic engineering in a medical sense?
Looking at ways to treat HIV, sickle cell anemia, Huntington's and CF.
789
Antibiotic resistance is an example of...
Evolution through natural selection.
790
Variation can be...
Genetic/inherited (resulting in a range of phenotypes), environmental (affects a range of phenotypes.
791
Nasal Cavity
Air warmed and filtered as it enters the body.
792
Trachea
Brings air into the lungs. Supported by rings of cartilage that prevent it collapsing.
793
Bronchus
Branches off the trachea to bring air into the lungs -supported by cartilage rings.
794
Bronchiole
Branch off the bronchi.
795
Alveoli
Small air sacs that are the site of gas exchange.
796
Lung
Organ where gas exchange occurs.
797
Ribs
Protect internal organs of the thorax.
798
Thorax
Part of the body between the neck and abdomen.
799
Intercostal muscles
Muscles between the ribs that aid breathing.
800
Diaphragm
Sheet of muscle below the ribs that aids breathing.
801
Pleural membranes
Thin layers that reduce friction between the lungs and inside of the chest wall during breathing.
802
Pleural Fluid
Fluid found in the pleural cavity (between the pleural membrane layers). It further reduces friction during breathing.
803
Inhalation
Intercostal muscles contract, ribs move up and out, diaphragm contracts, moving downwards, thorax increases in vol. and pressure decreases, causing air to enter the lungs.
804
Exhalation
Intercostal muscles relax, ribs move down and in, diaphragm relaxes, returning to its domed shape, thorax decreases in vol. and pressure increases, forcing air out of the lungs.
805
What can ECGs be used to do?
Monitor heart activity.
806
What does ECG stand for?
Electrocardiogram.
807
ECG
Looks at the electrical activity of the heart which is what controls the heart's activity. Sensors attached to the body are couple w/ a machine, that gives an ECG reading. Normal and abnormal activity can be identified.
808
Digestion
The breakdown of large, insoluble molecules of food into smaller, soluble molecules.
809
Rectum
Stores faeces prior to egestion.
810
Anus
Where faeces are egested.
811
Peristalsis
The process by which food moves through the digestive system - a wave of muscle contractions in the gut wall which forces food down the gut.
812
Absorption
Involves the small, soluble molecules from digestion being taken into the bloodstream through the wall of the intestine.
813
Ingestion
Intake of substance into the body via the mouth e.g. through eating and drinking.
814
Assimilation
The movement of digested food molecules into the cells where they are used.
815
Egestion
The passing of undigested food as faeces through the anus.
816
Excretion
The removal of waste products from the body and substances that are in excess.
817
Urinary system
Includes the kidneys, ureters, bladder and urethra.
818
Lifestyle changes which can be made to manage/treat cardiovascular disease?
Reducing smoking, more exercise, and a balanced diet.
819
What controls the natural, resting heart rate?
Natural pacemaker.
820
When can artificial pacemakers be used ?
If the individual has an irregular heartbeat.
821
Can genetics act as a risk factor to cardiovascular disease?
Yes, there are six genetic variants associated with CHD.
822
Fatty deposits in the coronary arteries are known as...
Plaques
823
Coronary Bypass Surgery
Coronary heart disease can be treated using bypass surgery -involves taking a healthy blood vessel from another part of the body and surgically inserting it so the blocked vessels are bypassed.
824
Anti-coagulants
Prevents arteries becoming blocked, reducing the risk of CHD. Can cause excessive bleeding if a person is wounded.
825
Anti-platelets
Prevents clots forming in arteries and thus, reduces the risk of CHD.
826
Anti-hypertensives
Can reduce blood pressure, protecting arteries so that their walls are not damaged and reduces the risks of plaques forming.
827
Prophylactic Treatment
Preventative treatment
828
Ecosystem
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
829
Interdependence
Describes how organisms in a community depend on other organisms for vital services.
830
Some species live together in a...
Symbiotic relationship
831
Mutualism
If it provides some benefit or resource to the other species, for instance providing nutrients, it is known as a mutualistic relationship.
832
Parasitism
Involves taking nutrients from another species, to the detriment of other species.
833
Commensalism
Is where there is no damage caused to either species, and there is often mutual benefit.
834
Pyramids of Biomass
Shows the relative biomass @ each trophic level.
835
Carbon cycle -photosynthesis.
Carbon dioxide is removed from the air in photosynthesis by green plants and algae. Carbon used to make carbs, proteins and fats. Plants are eaten, transferring carbon up the food chain.
836
Carbon cycle - respiration.
Carbon dioxide is returned to the air when plants, algae and animals respire. Decomposers respire while they return nutrients to the soil.
837
Carbon cycle - combustion.
Carbon dioxide is returned to the air when wood and fossil fuels are burnt - as they contain carbon from photosynthesis.
838
When biological material decays...
It produces compost.
839
Optimum conditions for decomposition?
Temperature, oxygen availability, water availability, number of decay organisms.
840
Decomposition
The breakdown and digestion of biological material by organisms called decomposers.
841
Decomposers
Include microorganisms - bacteria and fungi - and detritus feeders.
842
Microorganisms decompose waste anaerobically to produce...
Methane gas
843
Methane gas can be burnt as...
Fuel
844
_____ Generators are used to produce methane...
Biogas.
845
The sun's energy causes...
Water to evaporate from the sea and lakes, forming water vapour.
846
Water vapour is also formed as a result of...
Transpiration.
847
Water vapour...
Rises and condenses to form clouds.
848
Specific Heat Capacity Equation
Δ E = m c Δ θ
849
Specific Latent Heat
E = mL
850
Specific Latent Heat word equation
Energy to change state = mass x specific latent heat
851
Magnetic force on a current-carrying conductor
F = BIl
852
Magnetic force on a current-carrying conductor word equation
Force = magnetic flux density x current x length of conductor in a magnetic field.
853
Transformer coil equation
Vp / Vs = Np / Ns
854
Transformer current equation
VpIp = VsIs
855
Pressure in a fluid...
Pressure = height of column x density of fluid x gravitational field strength
856
Planets in order from the sun...
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
857
A planet is...
A body that orbits a star, is massive enough for its own gravity to make it round-shaped - has 'cleared its neighbourhood' of smaller objects around its orbit.
858
Moon
A natural object which orbits a planet.
859
How old is the universe?
Roughly 13.8 billion years ago.
860
Nuclear fusion
Two small nuclei fuse together to form one large nucleus - releasing energy in the reaction.
861
When are all naturally occurring irons up to iron produced?
In fusion in stars.
862
When are elements heavier than iron produced?
In the supernova.
863
How are elements heavier than iron distributed?
Across the universe in the supernova explosion.
864
Orbits of planets...
Circular
865
Artificial Satellite
Something man-made which is in orbit of the Earth.
866
In circular orbit...
There is changing velocity despite constant speed as the body constantly changes direction.
867
If the speed of an orbit changes...
The radius of orbit also changes.
868
Doppler Effect
Observed frequency of waves emitted by a moving object appear changed.
869
Red-shift
An observed increase in the wavelength of light from most distant galaxies.
870
The further away the galaxies...
The faster they are moving and the bigger the observed increase in wavelength.
871
Big Bang Theory
Suggests the universe began from a very small region that was extremely hot and dense.
872
Red-shift supports the Big Bang Theory because...
It shows that the universe is expanding - must once have been smaller.
873
Observations of supernovae suggest...
That the furthest away galaxies are moving away from us even faster.
874
Absorption spectrum...
A spectrum containing every wavelength of light but with dark lines where certain wavelengths have been absorbed.
875
Universe is expanding...
Slower than epected.
876
Scientists predict what % of the universe is dark energy?
68%
877
Scientists predict what % of the universe is dark matter?
27%
878
Stars begin life as...
A cloud of dust & gas - a nebula.
879
What is the next stage in the formation of stars after a nebula?
Gravity causes the nebula to collapse and the temperature rises to millions of degrees celsius - forms a protostar.
880
If the temperature is high enough in a protostar...
Hydrogen will join in nuclei fusion to form helium. Releases a huge amount of energy. Protostar is now a main sequence star.
881
What happens to a main sequence star which is the same size as the sun...
Red Giant - White Dwarf - Black Dwarf
882
Red giant formation...
When its hydrogen fuel source runs out, the outwards force due to fusion is lower than the inward force due to gravity - the star therefore collapses, temp. increases, so helium nuclei join to form heavier elements. Expands to form a reactant.
883
White dwarf
Red giant stops fusing helium and shrinks to become a white dwarf.
884
Black dwarf
White dwarf is no longer carrying out nuclear fusion - the temperature of the star decreases until the energy it emits is less significant - Black dwarf star formed.
885
What happens to a main sequence star greater in size that the sun?
Red Super Giant - Supernova - Black hole or neutron star.
886
Red Super Giant
Star' Hydrogen fuel begins to run out - expands to form a Red Super Giant.
887
Supernova
After it becomes a Red Super Giant, it eventually stops carrying out nuclear fusion & the star goes into supernova.
888
Black Hole
Large gravitational force - not even light can escape from.
889
Neutron Star
Made of neutrons densely packed together.
890
Geostationary Satellite
Orbit once every 24 hours, points to the same point of Earth.
891
Moon's orbit around Earth is...
Virtually circular.
892
A moon...
Natural object which orbits a planet.
893
Artificial Satellite
Something man-made which is in orbit of the Earth.
894
Orbit
The curved path of one celestial object or spacecraft around another celestial object.
895
Planet is trying to move in...
Instantaneous Velocity
896
Amount of energy carried by a photon depends on...
The frequency of the radiation.
897
Types of radiation which can cause ionisation (EM spectrum)?
UV, X-rays, Gamma
898
Ionisation
When radiation hits an atom or molecule, it can sometimes have enough energy to remove an electron and change the atom + molecule.
899
Detectors
Objects that absorb infrared radiation.
900
What will absorb / stop beta radiation?
A sheet of aluminium, approx 5mm.
901
In beta decay, the mass number of the parent nucleus...
Stays the same.
902
Activity
Rate at which decay occurs.
903
Range of gamma radiation
Unlimited
904
Half-life
The time taken for number of radioactive nuclei in a sample to halve or the time taken for count rate (or activity) from a sample to fall to half its initial value.
905
An irradiated object does not...
Become radioactive itself.
906
Ionising power of beta radiation...
Moderate
907
Radioactive Decay
An unstable nucleus changes to become more stable and gives out radiation.
908
Types of radiation
Alpha, Beta, Gamma
909
Radius of an atom
0.1nm
910
Ionising power of radiation
How likely it is to ionise atoms which it comes into contact with.
911
Emission of radiation from an atom may lead to...
Electrons moving to a lower energy level.
912
Contamination
The unwanted presence of materials containing radioactive atoms.
913
What will absorb / stop gamma radiation?
Several cm's of lead.
914
Range of Beta radiation in air.
Approximately 1m.
915
What will absorb / stop alpha radiation?
Paper/skin.
916
If ionisation happens in DNA, it can...
Cause mutations which may result in cancer.
917
Ionising Power of Gamma radiation
Low ionising Power
918
Count rate
Number of decays recorded each second by a Geiger-Muller tube.
919
Units of activity
Bq - Becquerels
920
Ionising Power of Alpha radiation
Very High Ionising Power
921
Range of Alpha radiation
Short - 5 cm in air.
922
Count rate
Number of counts / time
923
Activity
Activity of material x mass
924
Random nature of radioactive decay?
Cannot predict which nuclei will next decay or when it will decay.
925
Medical radioisotopes have to have a short half-life to...
Reduce damage to tissues / organs.
926
Braking Distance
The distance travelled in the process of coming to a stop.
927
Thinking Distance
The distance travelled in the process of braking.
928
Stopping Distance
Braking Distance + Thinking Distance
929
Inertia
The property of an object to remain in a constant state unless acted on by an external resultant force.
930
Walking velocity
1.5 m/s
931
Running velocity
3 m/s
932
Cycling velocity
6 m/s
933
Boyle's Law
As pressure increases, volume decreases, because they are inversely proportional. As you go down to an area of higher pressure, gas will compress proportionally.
934
Change of state from liquid - solid?
Solidifying / Freezing
935
Physical State
A change that does not produce a new substance. If the change is reversed, the substance recovers its original properties.
936
What is the Kinetic Theory of Matter?
Particle model of solids, liquids & gases which describes their properties.
937
Random motion
Unpredictable path that an individual gas particle follows.
938
Internal energy
The total energy in the kinetic & potential stores of all the particles (atoms & molecules) that make up a system.
939
Horizontal line on a temperature vs time graph...
Represents a change of state.
940
Reversible Change
A change to a substance, which when reversed, allows the substance to recover its original properties.
941
Particles in a solid.
Strong forces, regular structure, packed close together and vibrate.
942
Specific Latent Heat of Vaporisation
The amount of energy required to change one kg of a liquid into a gas (vapour) w/ no change in temperature.
943
Evaporating
When a liquid changes to a gas below the b.p.
944
Chemical Change
A change in which the chemical bonds are broken & reformed to form new products.
945
Gas - density
Least dense state of matter.
