Y8 Science Flashcards
(295 cards)
1
Q
On which part of the periodic table do you find non-metallic elements?
A
Right hand side
2
Q
What is the smallest part of an element that can exist?
A
Atom
3
Q
Group 1 in the periodic table is also known as
A
Alkali metals
4
Q
Group 7 in the periodic table is also known as
A
Halogens
5
Q
Helium, Neon, Argon and Krypton are found in group 0 and they are examples of
A
Noble gases
6
Q
Define a molecule
A
A defined group of non-metal atoms that are chemically bonded
7
Q
Define a compound
A
Two or more elements chemically bonded in a fixed ratio.
8
Q
Potassium phosphate contains potassium, phosphorous and what else?
A
Oxygen
9
Q
Define a mixture
A
Two or more elements or compounds are present without being chemically bonded together.
10
Q
Define a lattice
A
A regular three-dimensional arrangement of atoms (or ions) in a solid
11
Q
How does mass change in a chemical reaction?
A
It doesn’t. The total mass of reactants = total mass of products
12
Q
Which particles are found in the nucleus?
A
Protons and neutrons
13
Q
What is the charge of an electron?
A
Negative
14
Q
Which two subatomic particles have the same mass?
A
Protons and neutrons
15
Q
What is the overall charge of an atom?
A
Zero
16
Q
What does the atomic number tell us?
A
Number of protons. This determines the element.
17
Q
What does the mass number represent?
A
Number of protons + neutrons
18
Q
What is the charge of a neutron?
A
Zero. No charge
19
Q
How many electrons can fit on the first electron shell?
A
2
20
Q
What is the maximum number of electrons that can fit on the second electron shell?
A
8
21
Q
What can electron shells also represent?
A
Energy levels
22
Q
Write the word equation for aerobic respiration
A
glucose + oxygen -> carbon dioxide + water + (energy)
23
Q
From which system does the body obtain glucose for respiration?
A
The digestive system
24
Q
In which part of our cells does respiration mainly occur?
A
In the mitochondria
25
What are the products of respiration?
Carbon dioxide, water
26
How do we test for carbon dioxide?
Bubble through limewater; the limewater turns cloudy.
27
The word "aerobic" indicates the presence of which gas?
Oxygen
28
Which unit is energy usually measured in?
joules, J
29
How many joules are there in 1 kilojoule?
1000J
30
What is the symbol for kilojoule?
kJ (lower case k, capital J)
31
If a food is high in energy, which nutrient/s is it likely to contain?
Lipids/fats, carbohydrates
32
List the 7 nutrients needed by the human body
carbohydrates, proteins, lipids, vitamins, minerals, water, fibre
33
Foods high in which group help repair muscles?
Protein
34
Why is fibre needed in our diet?
Add bulk to food to help it pass through the digestive system; prevents constipation
35
Scurvy can occur when we don't get enough of which vitamin?
C
36
Give 2 sources of vitamin C
Fruit and vegetables
37
Rice, potato and bread are good sources of
Carbohydrates
38
Meat, fish and nuts are good sources of
Protein
39
Sugar and starch are both types of
Carbohydrate
40
Which test do we use to detect for the presence of starch?
Iodine
41
When testing for starch what colour change indicates a positive result?
Brown to black
42
Which test do we use to detect for the presence of sugar?
Benedicts
43
When testing for sugar what colour change indicates a positive result?
Blue to red
44
Which test do we use to detect for the presence of protein?
Biuret
45
When testing for protein what colour change indicates a positive result?
Blue to purple
46
Which test do we use to detect for the presence of fats?
Ethanol
47
When testing for fats what change indicates a positive result?
Cloudy emulsion formed
48
What is digestion?
The process of breaking down food into substances our body can absorb and use
49
Where does mechanical digestion mainly occur?
In the mouth
50
List the organs the food will travel through on its way through the digestive system
Mouth, oesophogus, stomach, small intestine, large intestine, rectum, anus
51
Which nutrient starts to be chemically digested in the mouth?
Carbohydrate
52
Where does digestion of protein take place?
Stomach, small intestine
53
Where does digestion of lipids take place?
Small intestine
54
Which organ produces carbohydrase, protease and lipase?
Pancreas
55
What is the purpose of hydrochloric acid in the stomach?
Provides the right pH for the protease enzymes; kills bacteria
56
What is the purpose of bile in the digestive system?
Neutralise the acid which was added to food in the stomach to give the best pH for enzymes to work. Break down (emulsify) fat
57
Where is bile produced?
Liver
58
Where is bile stored?
Gall bladder
59
The site of maximum absorption in the digestive system is...
The small intestine
60
During digestion, carbohydrate is broken down into
Glucose
61
During digestion, protein is broken down into
Amino acid
62
During digestion, lipids are broken down into
Fatty acid and glycerol
63
Which enzyme digest protein?
Protease
64
Which enzyme digests carbohydrates?
Carbohydrase
65
Which enzyme digests fats?
Lipase
66
Why is fibre not digested in the body?
Our bodies do not have enzymes that can digest fibre
67
Why are vitamins and minerals not digested in the body?
They are small enough to be absorbed without digestion
68
What is the purpose of bacteria in our gut?
Digest food we cannot (e.g. cellulose) to give us essential nutrients (e.g. vitamin K)
69
In which part of the digestive system does water and mineral absorption take place
The large intestine
70
How is the small intestine adapted to increase the rate of absorption?
Villi and microvilli to increase surface area; a good blood supply to transport nutrients; mucus for lubrication; glucose moves from a high concentration in the intestine to a lower concentration in the blood.
71
What are the optimum conditions for amylase?
Neutral pH, 37 degreesC
72
What happens to an enzyme if it is boiled or exposed to a strong acid?
It is denatured
73
What is the scientific name for the windpipe?
Trachea
74
The trachea divides into two ________. These then divide into __________
Bronchi. Bronchioles
75
What are the air sacs at the end of each bronchiole called?
Alveoli
76
Breathing in and out is also known as...
ventilation
77
When we inhale, the volume inside the thorax ____________ so the pressure inside the thorax _____________
Increases. Decreases.
78
When we exhale, the diaphragm relaxes and moves upward/downward?
upward
79
What features do alveoli have to maximise gas exchange?
Large surface area; concentration gradient (oxygen and carbon dioxide can diffuse); good blood supply; capillary wall only 1 cell thick
80
Write the word equation for anaerobic respiration in cells
glucose -> lactic acid
81
Which releases more energy - aerobic or anaerobic respiration?
aerobic
82
What is anaerobic respiration in yeast cells known as?
Fermentation
83
Give an example of where fermentation is used
Brewing or baking
84
What are the products of the fermentation reaction?
Ethanol, carbon dioxide
85
A wave transfers _____________. It does not transfer ______________.
Energy, matter
86
In a _______________ wave the vibration of the particles is perpendicular to the direction of energy transfer
transverse
87
In a _______________ wave the vibration of the particles is parallel to the direction of energy transfer
longitudinal
88
Transverse wave - the _______________ of the particles is __________________ to the direction of energy transfer
vibration/oscillation, perpendicular
89
Longitudinal wave - the _______________ of the particles is __________________ to the direction of energy transfer
vibration/oscillation, parallel
90
What feature of the wave is shown on the diagram
Wavelength
91
What feature of the wave is shown on the diagram
Amplitude
92
Which letter represents the amplitude of a wave?
B
93
In a longitudinal wave, areas where the particles are pushed together are called _________________ and areas where the particles are spread out are called _________________
compressions, rarefactions
94
A louder sound will have a higher __________________.
amplitude
95
A high-pitched sound will have a higher _________________
frequency
96
Give an example of a longitudinal wave
sound
97
Give an example of a transverse wave
light (also radio, microwaves, infra-red, UV, X-ray, gamma ray, water waves)
98
An object which gives off light is known as....
luminous
99
How can we see non-luminous objects?
because light is reflected off the object
100
When light hits and object and "stops" it is known as...
absobtion
101
When light hits and object and bounces off it is known as...
reflection
102
A material that lets light through without scattering is known as...
transparent
103
What is an opaque material?
A material that does not let light pass through
104
An object that scatters light as it passes through is known as...
transluscent
105
How does the angle of incidence compare to the angle of reflection?
they are equal/the same
106
If we are drawing a reflected ray, which step is missing
1. Extend the incident line to the surface.
2.
3. Measure angle of incidence.
4. Construct your angle of reflection.
Draw on the normal line
107
What is refraction?
The change in direction of a wave when it changes speed.
108
When does refraction occur?
When a wave moves into a different substance
109
If the speed of a wave decreases as it moves into a new substance it will bend _____________ the normal
towards
110
If the speed of a wave increases as it moves into a new substance it will bend _____________ the normal
away from
111
Draw the path of the light
112
Draw the path of the light
113
Draw the path of the light
114
When the angle of incidence is greater than the critical angle, what will happen to the light?
All the light will be reflected/total internal reflection.
115
If all the light is reflected with a material (e.g. a piece of glass), what is this known as?
Total internal reflection
116
Give two examples of where total internal reflection is found in real-life applications
Periscopes (submarines), internal cameras (medicine), fibre-optic communications e.g. fast broadband, inspecting aircraft engines
117
What is the name of the coloured circle around the pupil. It controls the size of the pupil
Iris
118
What is the purpose of the lens in the eye?
To focus light onto the retina
119
What do you call the black part of the eye? It is the opening that lets light in
Pupil
120
What is the retina?
Light-sensitive layer at the back of the eye, made up of rods and cones
121
What is the purpose of the optic nerve?
Carries messages from the retina to the brain.
122
Why do we end up with an inverted image formed on our retina when we look at an object?
Because light is refracted by the cornea and lens in our eye.
123
What three colours of light can our eyes detect?
red, green, blue
124
What are the colours of the spectrum that make up white light?
Red, Orange, Yellow, Green, Blue, Indigo, Violet (use ROY G. BIV or Richard Of York Gave Battle In Vain to help you remember the order)
125
The colour of a light depends on what feature of a wave?
Frequency
126
When light enters a prism it splits into the colours of the spectrum, what do we call this effect?
Dispersion
127
Why does a blue object appear blue when a white light is shone upon it?
It reflects blue light. It absorbs all other colours of light.
128
Why do black objects appear black?
They absorb all colours that are shone on them. No light is reflected.
129
When red and green light is combined, what colour is formed?
Yellow
130
When red and blue light is combined, what colour is formed?
Magenta
131
When blue and green light is combined, what colour is formed?
Cyan
132
If a sound is becoming lower pitched, what is decreasing?
The frequency
133
If a sound is becoming lower in volume, what is decreasing?
The amplitude
134
What formula can we use to calculate the speed of sound?
speed = distance/time
135
Do sound waves travel fastest in solid, liquid or gas?
Solid
136
Do light waves travel fastest through a solid, liquid or gas?
Gas (light travels fastest through a vacuum)
137
When calculating the speed of sound using an echo, what must you remember
The echo travels to an object and back again (you may need to double the distance or halve the time provided - take care!)
138
List 3 key signs of a chemical reaction
* A colour change.
* A flame or explosion.
* Reaction gets hot or cold by itself.
* A gas is produced in the reaction without heating.
* A solid is produced in the reaction without cooling.
139
What happens in a chemical reaction?
Some bonds are broken and others form to make new chemicals
140
What does not happen in a physical change?
No bonds are broken or formed
141
When balancing a chemical reaction, what must we not change?
The chemical formulae i.e. the "small" numbers cannot change
142
What do we mean by a balanced chemical reaction?
There are the same number of atoms of each element in the reactants and in the products e.g. if there are 2 oxygen atoms in the reactants, there must be 2 in the products
143
What is wrong with this balanced equation?
2Ca + O2 = 2CaO
An = symbol is used instead of an arrow (the 2 in O2 should also be a subscript)
144
How do you identify an exothermic reaction?
An increase in temperature as energy is transferred to the thermal store of the surroundings
145
How do you identify an endothermic reaction?
A decrease in temperature as energy is transferred from the thermal store of the surroundings.
146
What is oxidation?
When an element combines with oxygen to form a compound
147
What is combustion?
When a fuel rapidly reacts with oxygen transferring energy to the thermal store of the surroundings (high temperature)
148
Rusting would be an example of what type of chemical reaction?
Oxidation
149
Are metal oxides acidic or alkaline?
Alkaline e.g. sodium hydroxide is a drain cleaner
150
Are non-metal oxides acidic or alkaline?
Acidic
151
What happens when a compound combusts?
Each element in the compound forms an oxide
152
Methane is a hydrocarbon (it contains carbon and hydrogen), what products form when it combusts
Water (oxidation of hydrogen) and carbon dioxide (oxidation of carbon)
153
What is thermal decomposition?
A compound is broken down by heat
154
What is a test for carbon dioxide?
Bubble through limewater (the limewater turns cloudy)
155
What happens in displacement?
A more reactive metal takes the place of a less reactive metal in a compound
156
Why are alkali metals (group 1 elements) reactive?
They have 1 electron in their outer shell
157
Why are halogens (group 7 elements) reactive?
They have 7 electrons in their outer shell
158
Why are nobel gases not reactive?
They have a full outer shell
159
If a less reactive metal is added to a salt solution containing a more reactive metal, what will happen?
Nothing (no reaction will occur)
160
What do all acids have in common?
They contain hydrogen
161
An acid releases what into solution
Hydrogen ions (positive)
162
An alkali releases what into solution?
Hydroxide ions (negative)
163
pH 0 is a strong...
Acid
164
pH 14 is a strong...
Alkali
165
What is neutralisation?
The hydrogen ions from an acid combine with the hydroxide ions from the alkali to form water
166
Acid + alkali -> what are the products?
Salt + water
167
Acid + Metal carbonate -> what are the products?
Salt + water + carbon dioxide
168
What is a salt?
Hydrogen ions in an acid have been replaced by a metal
169
What is a catalyst?
A chemical that speeds up a chemical reaction without being used up in the reaction.
170
Give an example of a biological catalyst
Enzyme (lipase, amylase, carboydrase, protease)
171
Catalysts ___________ the _________ barrier which ___________ the rate of reaction
Catalysts REDUCE the ENERGY barrier which INCREASES the rate of reaction
172
Give 3 examples of diatomic elements (i.e. they hang around in pairs!)
Oxygen, Nitrogen, Hydrogen, any halogen (group 7 element)
173
True/False - all combustion reactions are oxidation reactions
t
174
Where on the periodic table are many catalysts found?
Transition metals
175
A material which easily allows an electric current is
an electrical conductor
176
A material which does not allow an electric current is
an electrical insulator
177
Name some good electrical conductors
Any metal (some are better than others!), graphite (a form of carbon), salt water
178
Name some good electrical insulators
Wood, plastic (most non-metals in fact)
179
Draw the circuit symbol for a cell
180
Draw the circuit symbol for a battery
181
Draw the circuit symbol for a bulb
182
Draw the circuit symbol for a switch
183
Draw the circuit symbol for a variable resistor
184
Draw the circuit symbol for an ammeter
185
What instrument is used to measure current?
Ammeter
186
What does an ammeter measure?
Current
187
What is the unit of current and what is its symbol?
Amperes, A
188
If I increase the number of cells in my battery the current will...?
Increase
189
When the charge moves through the cell it gains...?
energy
190
Energy per unit charge is also known as....
potential
191
What is the unit of potential?
volt, V
192
If I connect more bulbs in series with each other the resistance will...and the current will....
resistance will increase and the current will decrease
193
What is current?
The amount of charge passing a point each second
194
At a junction in a circuit what is the important rule to remember?
total current in = total current out
195
Which poles of a magnet attract each other?
The opposite poles (North and South)
196
What happens when like poles of magnets come together
They repel
197
Give some examples of magnetic materials
Iron, Steel, Cobalt, Nickel
198
Give some examples of non-magnetic materials
Plastic, Wood, Paper, Rubber, Glass
199
Why does the Earth have a magnetic field
The core of the earth is a rotating ball of Iron
200
What is a magnetic field?
The region around a magnet where other magnetic materials experience a force
201
How are magnetic fields represented in diagrams?
Magnetic field lines
202
How could you visualise the field around a magnet?
Iron filings, or using a compass
203
Draw the magnetic field around a bar magnet
204
Draw the magnetic field around the Earth
Remember - the Earth's geographic north pole is a magnetic south pole (we still call it magnetic north when referring to where our compass needle points!)
205
What is the shape of a magnetic field around a wire and how can we tell the direction of the field lines?
Circular. Right hand "thumbs up" rule. Thumb points in the direction of the current, the fingers curl in the direction of the field
206
When a current flows in a wire a magnetic field is generated. What do we call this effect?
Electromagnetism
207
Name 3 ways to increase the strength of the magnetic field around a solenoid
* Increase the current
* Increase the number of turns on the coil
* Add an iron core
208
What is one of the major advantages of an electromagnet compared to a permanent magnet
Electromagnets can be switched on and off
209
What is a relay circuit used for?
To activate high voltage circuits using low voltage circuits (this protects the user from high currents)
210
List some uses of electromagnets
In relays (e.g. to switch of floodlights or x-ray machines in hospitals), in scrapyards to move parts, maglev trains, in electric motors, in rollercoaster braking
211
What are the seven signs of life?
Movement, Respiration, Sensing, Growth, Reproduction, Excretion, Nutrition (MRS GREN)
212
Where does most of the energy for life come from?
The Sun
213
Which reaction is used by most producers to store energy?
Photosynthesis
214
True or false: all living things carry out respiration
t
215
Where in the cell does aerobic respiration occur?
Mitochondria
216
Where in the cell does anaerobic respiration occur?
Cytoplasm
217
What is the word equation for photosynthesis?
Carbon dioxide + Water --> Glucose + Oxygen
218
What is the word equation for aerobic respiration?
Glucose + Oxygen --> Carbon dioxide + Water
219
What is the purpose of respiration?
Provides energy for other life processes
220
What is the name for the polymer made from glucose that is used to store energy?
Starch
221
What is the chemical test for starch?
Iodine solution turns black
222
Name two enzymes that break down starch
Amylase, Carbohydrase
223
A polymer is a large chemical made up of repeat units with what name?
Monomers
224
Which part of a plant typically has the most starch?
The root (or tuber)
225
In a food chain, what do the arrows represent?
The transfer of energy
226
Define a producer
An organism that produces its own nutrients
227
Define a consumer
An organism that gets its nutrients from other organisms
228
Define a herbivore
An organism adapted to consume plants
229
Define a carnivore
An organism adapted to consume animals
230
Define a predator
An animal that hunts other animals
231
Define a prey
An animal that is hunted by other animals
232
Define a top (Apex) predator
An organism at the end of the food chain, which has no natural predators
233
What is the technical term for each layer of a food chain / web?
A trophic level
234
If the number of prey species decrease, what is likely to happen to their predators?
After a delay, the predator species will also decline
235
What is the name for a graph showing the population in each level of a food chain?
Pyramid of numbers
236
What is the name for a graph showing the size of organism in each level of a food chain?
Pyramid of biomass
237
Name the process by which a chemical can increase in concentration higher up a food chain
Bioaccumulation
238
Give an example of a pesticide
DDT
239
What is the name for the female reproductive system in a plant?
Carpel
240
What is the name for the male reproductive system in a plant?
Stamen
241
List the three components of the female reproductive system in a plant
Stigma, style, ovary
242
List the two components of the male reproductive system in a plant
Anther, filament
243
What is the purpose of a petal?
To attract pollinating species
244
What is the purpose of a sepal?
Protecting the flower until it blooms, and then supporting the flowerhead
245
Name the male gamete in a plant
Pollen
246
Name the female gamete in a plant
Ovules
247
After fertilisation, what does the ovule become?
Zygote, then embryo, then a seed.
248
After fertilisation, what does the ovary become?
Fruit
249
What is the risk caused by having adjacent male and female reproductive organs?
Self-pollination
250
How do plants avoid pollinating their own flowers?
Either having separate male and female flowers, or having the male and female organs develop at different times.
251
Name the two types of plant fertilisation
Insect pollination or wind pollination
252
A brightly coloured flower is likely to be fertilised by?
Insects
253
A flower with large fluffy parts is likely to be fertilised by?
Wind
254
Asexual reproduction produces offspring identical to the parents. What are these called?
Clones
255
List the main methods of seed dispersal
Wind, Animal (external), Animal (internal), Water, Explosive
256
Characteristics that can be inherited must be controlled by what?
DNA (genetics)
257
The largest groups for classifying organisms are?
Domains
258
Define a species
A group of organisms capable of producing fertile offspring
259
What is the name for the infertile offspring of two similar species?
Hybrid (e.g. mule, liger, tigon)
260
What is the name for the way in which an organism is suited to its habitat?
Adaptation
261
What is a gravitational field?
The region around an object with mass where other objects experience weight
262
What is weight?
A force experienced by an object with mass that is inside a gravitational field
263
Give the formula for weight
weight = mass x gravitational field strength
264
What is the gravitational field strength of the earth?
10 N/kg (or 9.8)
265
What are the units of mass?
kg (kilograms)
266
What are the units of force?
N (newtons)
267
Name the planets
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
268
Name the five largest dwarf planets
Pluto, Eris, Ceres, Makemake, Haumea
269
Why is Venus considered a "terrestrial" planet?
It is made of rock
270
Which planets are the ice giants?
Uranus and Neptune
271
What is meant by a "Jovian planet"
A planet that is similar to Jupiter (a gas giant)
272
What is the speed of light?
300,000,000 m/s
273
How long does it take for light to travel from the Moon to the Earth?
1.25 seconds
274
How long does it take for light to travel from the Sun to the Earth?
500 seconds (approximately 8 minutes)
275
What do stars form from?
Nebulae
276
What is the name for most stars in the stable portion of their life cycle?
Main sequence star
277
What is the name for the hot ball of gas that begins to form a star?
Protostar
278
Which colour of star is the hottest?
Blue
279
Which colour of star is the coolest?
Red
280
Name the closest star to the solar system other than the sun
Proxima Centauri
281
Give the name for the whole of space
Universe
282
What is a group of billions of stars called?
Galaxy
283
What is the name of the galaxy that the solar system is in?
Milky Way
284
What is a year?
The time taken for a planet to orbit its star
285
What is a day?
The time taken for a planet to rotate fully on its axis
286
How long does it take for the Earth to orbit the Sun?
365.25 days
287
What is the main factor controlling the length of a year for a planet?
The distance the planet is from the sun.
288
Why does the Earth experience seasons?
The axis of rotation is tilted around 23 degrees from the plane of its orbit
289
Mercury does not have a tilted axis of rotation. Will it experience seasons?
No
290
Why is winter cooler than summer?
Away from the equator, sunlight is spread over a larger area of ground so warms it less. The days are also shorter, so there is less time for the ground to warm up.
291
If something is moving in a circle e.g. a planet orbiting the sun, in which direction is the force?
Towards the centre of the circle
292
Which force causes a moon to orbit a planet
gravitational force (directed towards the centre of a circle)
293
Draw the magnetic field around a bar magnet
294
Draw the magnetic field around the Earth
Remember - the Earth's geographic north pole is a magnetic south pole (we still call it magnetic north when referring to where our compass needle points!)
295
Draw the gravitational field around the Earth
It will be the same shape for other planets and stars
