Nat 5 Chemistry Part 1 Flashcards
(159 cards)
1
Q
Signs of chemical reaction?
A
Effervesance
Colour Change
New substance formed
Energy Change
Endothermic activity
Exothermic activity
2
Q
What does endothermic mean?
A
Endothermic means take in light
3
Q
What does exothermic mean?
A
Exothermic means gives out light
4
Q
What is the collision theory.
A
In order for a chemical reaction to occur, the atoms or molecules need to make contact with each other. A chemical reaction only occurs when a successful collision occurs. A successful collision is only some of the collisions. The more successful collisions the faster the reaction will go.
5
Q
How can reactions be sped up?
A
Increasing the temperature
Increasing the concentration
Decreasing the particle size
Use of a catalyst
6
Q
What is the rate of chemical reaction defined as?
A
The change in the concentration of a reactant or product over a period of time.
It can be expressed by the mathematical equation: Rate = Change / Time.
7
Q
What does big triangle stand for?
A
Big change
8
Q
What different kinds of chemical change are there?
A
Concentration
Temperature
volume of gas produced
loss in mass
pH
9
Q
How to measure the rate of a reaction?
A
Collecting the volume of gas produced as the reaction proceeds.
10
Q
What does smaller particle size lead to in a reaction?
A
A faster rate of reaction.
11
Q
What different methods are there to monitor the rate of reaction.
A
Volume of gas produced
Temperature
pH
Pressure
Electrical Conductivity
Mass lost
12
Q
What is temperature collision theory?
A
If the temperature increases the particles move faster which increases the rate of reaction because of more collisions.
13
Q
What does higher temperature lead to in a reaction?
A
A faster reaction
14
Q
What does higher concentration lead to in a reaction?
A
A faster reaction
15
Q
What is the concentration collision theory?
A
If the concentration is increased there are more particles moving around causing more collisions which makes the reaction faster.
16
Q
What is the particle size collision theory?
A
If the particle size is decreased its surface area increases which makes more collisions happen which makes the reaction faster.
17
Q
What is the catalyst collision theory?
A
A catalyst is never used up in a reaction. The reacting particles can collide more successfully with less energy when the catalyst is present.
18
Q
What are the element symbols for:
Hydrogen
Carbon
Iodine
Nitrogen
Sulfur
Vanadium
Chlorine
Magnesium
Calcium
Scandium
Argon
Silicon
A
H
C
I
N
S
V
Cl
Mg
Ca
Sc
Ar
Si
19
Q
Name the liquids in the periodic table?
A
Mercury
Bromine
20
Q
How many gases are in the periodic table?
A
11
21
Q
What are the gases in the periodic table?
A
Hydrogen, Helium, Nitrogen, Oxygen, Fluorine, Chlorine, Neon, Argon, Krypton, Xenon and radon.
22
Q
How many liquids are in the periodic table?
A
2
23
Q
What do elements in the same group have?
A
Similar chemical and physical properties. The same number of outer electrons.
24
Q
How is the periodic table arranged?
A
Vertically by Group
Horizontally by Period
25
Give the name, state and reactivity for groups:
1
7
8/0
Alkali metals, Metal, Reactive
Halogens, non - metals, Reactive
Noble Gases, non - metals, Unreactive
26
What are the elements between groups 2 and 3?
Transition Metals
27
What are elements made up of?
One type of atom.
28
What are compounds made off?
Two or more types of atoms.
29
What are atoms made up off?
Energy level / s / electron shell / s
proton / s
a nucleus
neutron / s
electron / s
30
Where are these subatomic particles found in an atom and whats their mass and charge:
Proton
Neutron
Electron
Nucleus, 1 amu, positive
Nucleus, 1 amu, neutral
On the energy level / s, near to 0, negative
31
What does the atomic number tell you.
The number of protons and electrons.
32
How to work out an atoms mass number?
Adding the protons and neutrons.
33
What is the formula for working out everything about an atom?
Formula:
neutrons
+
Protons=electrons=Atomic number
=
mass number
34
How many electrons can the first, second and third energy levels hold.
2
8
8
35
What do the elements in the same period have in common?
The same number of energy levels.
35
What name is given to this way of representing an atom?
12
C
6
Nuclide Notation
36
What is the atomic number, number of protons, electrons, neutrons and mass number in this element:
13
C
6
6
6
6
7
13
37
What is an isotope?
An atom of the same element with a different number of neutrons and mass number.
38
What is relative atomic mass?
The average mass of isotopes in an atom.
RAM (A.M.U)=(% of isotope 1 x mass)+(% of isotope 2 x mass) / 100
It will be closer to the mass of the most common isotope. If the RAM is halfway between the masses of the isotope, there is an equal mixture of isotopes.
39
What is an ion?
A charged atom.
An atom that has an unequal amount of protons as electrons.
40
What is the charge of an atom.
There is no charge because they have the same number of protons as electrons.
41
What is a cation?
An atom that loses electrons and become positively charged.
42
What is an ancion?
An atom that gains electrons and becomes negatively charged.
43
What happens when metals are placed into a flame.
The flame changes colour.
44
What is the colour of the flame for these metals:
Na+
Li+
K+
Ba 2+
Sr 2+
Ca 2+
Cu 2+
Yellow
Red / Pink
Orange / Purple
Light Blue
Red
Orange
Turquoise
45
What is covalent bonding?
The sharing of electrons.
46
What are the diatomic molecules and a memorable sentence for them?
Hydrogen (H2), Nitrogen (N2), Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2), Iodine (I2).
I2 H2ave N2o Br2ight O2r Cl2ever F2riends
47
How do you know if a chemical contains 2 elements joined together.
It ends in ide
48
How do you know if a chemical contains 2 or more elements with oxygen.
It ends with ite or ate
49
What do we use prefixes for?
It tells us how many of each atom there is in the formula.
50
What are the prefix numbers to 10?
mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca.
51
What is the valency of an element?
The combining power of an element.
52
Whats the valency of the elements in the groups 1 - 8.
1
2
3
4
3
2
1
0
53
State the step by step way of working out the formula of a compound.
Symbol Al O
Valency 3 2
Swap 2 3
Simplify Al2 O3
54
What do the roman numerals show in a compound with transition metals.
The valency of the transition metal.
55
What are the 3 extra rules for writing ionic formula?
1. Metals are always positive ions
2. non - metals are always negative ions
3. Valency is the size of the charge
56
What are the different shapes of molecules?
linear H --- F
Angular H --- O --- H
Triangular Pyramidal
H --- N
57
What are the different types of bonding?
Covalent Bonding
Ionic Bonding
Metallic Bonding
58
Give some descriptions of covalent bonding:
- Between non - metals
- Positive nuclei are attracted to the negative shared pair of electrons
- They can be molecular or networks
59
Give some descriptions of Ionic bonding:
- This is found in compounds made from metals and non - metals
- Compounds classified as ionic are made from ions not neutral atoms
- Ions are formed when an atom loses or gains one or more electrons
- The ionic bond is the electrostatic force of attraction between a positively charged metal ion and a negatively charged non - metal ion
- Ionic compounds form a regular repeating arrangement called a lattice
60
Give some descriptions of Metallic bonding:
- This is only found in metals
- In metallic bonding, the outer electrons are delocalised
- This produces a force of attraction between the positively charged metal ions and the negatively charged delocalised electrons
61
What is the summary of the types of bonding:
non - metal bonding -> covalent bonding
metal and non - metal -> ionic bonding
metals -> metallic bonding
62
What are intermolecular forces:
- Intermolecular forces are found between molecules which have covalent molecular bonding
- More forces between molecules will result in higher melting and boiling points
63
What do these mean:
(aq) (s) (l) (g)
Aqueous - solutions made using water
solid
liquid - pure liquid
gas
64
How would we know if something is a solid from there mpt and bpt.
mpt and bpt are above 20 degrees
65
How would we know if something is a liquid from there mpt and bpt.
mpt below 20 degrees
bpt above 20 degrees
66
How would we know if something is a gas from there mpt and bpt.
mpt and bpt below 20 degrees
67
Are the mpt and bpt low or high for: covalent molecular
covalent network
Low
high
68
What is the conductivity of these bondings:
Metallic
Covalent
Ionic solutions
Ionic solids
Conducts
doesn't conduct except graphite
conducts
doesn't conduct
69
Why can't ionic solids conduct.
The ions are not free to move
70
Why can ionic molten or solutions conduct
The ions are free to move
71
What does conduction need and why can metals and ionic compounds conduct.
Conduction needs the movement of
charged particles. Metals conduct because their charged particles are delocalised electrons and ionic compounds the charged particles are ions.
72
What is formula mass?
The sum of the masses of all of the atoms that it contains.
73
What is the equation to work out the mass of an element or compound?
mass = moles x gram formula mass
74
What is the equation to work out the moles of an element or compound?
moles = concentration x volume
moles = mass / gram formula mass
75
What is the step by step calculation to work out the mass of 2MgO when you have the mass of 2Mg which is 49g.
Step 1 Work out the moles of the known
Step 2 Mole ratio
Step 3 Work out the mass of the unknown
76
What is a heterogenous catalyst?
This is where the reactants are in a different state to the catalyst. So the reactants are gases and the catalyst is solid.
77
What is a homogenous catalyst?
This is where the reactants are in the same state as the catalyst. So the reactants are liquid and the catalyst is a liquid.
78
State the units for measuring reaction rate
The quantity of chemical – mass (g), volume of gas (cm3), or concentration (mol l-1).
AND
The unit of time – seconds (s), minutes (min), or hours (hr).
79
If a reaction produced 120cm3 of gas in 15 seconds, what is the average rate of reaction?
Average rate = ∆ Quantity ÷ ∆ Time
= 120 ÷ 15
= 8 cm3 s-1
80
What is the electron arrangement of
Carbon (6 electrons)
Lithium (3 electrons)
Calcium (20 electrons)
2,4
2,1
2,8,8,2
81
Why does a metal atom form a positive ion?
It loses an electron so that there are a greater number of positive protons than negative electrons so the charge is positive.
82
Why does a non-metal form a negative ion?
It gains an electron so there are more negative electrons than positive protons so the charge is negative.
83
What is RAM?
relative atomic mass
84
Why are Ions formed?
To obtain the stable electron arrangement of a noble gas.
85
An ion of Calcium has 18 electrons, 20 protons and 20 neutrons. what is the charge on this ion?
Ca2+
86
An Ion of Fluorine has 10 electrons, 9 protons and 10 neutrons. What is the charge on this ion?
F-
87
What is the nuclide notation for an atom of Calcium which has 20 electrons, 20 protons and 20 neutrons?
40
Ca
20
88
What is the nuclide notation for an ion of Magnesium which has 10 electrons, 12protons and 12 neutrons?
24
Mg2+
12
89
27
Al3+
13
How many protons, neutrons and electrons are present?
Protons =atomic number=13
Neutrons = mass number-atomic number=27-13=14
Electrons = protons -charge =13-(+3)=10
90
31
P3-
15
How many protons, neutrons and electrons are present?
Protons =atomic number=15
Neutrons = mass number-atomic number=31-15=16
Electrons = protons -charge =15-(-3)=18
91
What do we call the rows on the periodic table?
Periods
92
What do we call the columns on the periodic table?
Groups
93
How are the elements arranged in the periodic table?
Elements in the Periodic Table are arranged in order of increasing atomic number.
94
An element has an electron arrangement of 2,8,18,8,1 what group would it belong in?
Group 1
95
An element has an electron arrangement of 2,8,8 what group would it belong in?
Group 8 / 0
96
An element has an electron arrangement of 2,8,18,7 what group would it belong in?
Group 7
97
What is meant by an ionic lattice?
A lattice is a regular arrangement of ions where each positive ion is surrounded by negative ions and each negative ion is surrounded by positive ions.
98
Explain the physical properties of ionic compounds:
melting point and boiling point
solubility (water molecules surround ions)
electrical conductivity
- Ionic compounds have high melting and boiling points because strong ionic bonds must be broken in order to break down the lattice.
- Tend to be soluble in water.
- Ionic compounds conduct electricity only when molten or in solution, due to the breakdown of the lattice resulting in the ions being free to move
99
What are the two types of covalent structures?
discrete
network
100
Explain the physical properties of discrete molecular covalent compounds:
melting point and boiling point
solubility (water)
electrical conductivity
- Covalent molecular substances have low melting and boiling points as only weak forces of attraction between molecules are being broken.
- Covalent molecules tend to be insoluble in water but soluble in covalent type solvents.
- Covalent molecules never conduct except carbon graphite.
101
Explain the physical properties of covalent network compounds:
melting point and boiling point
solubility (water molecules surround ions)
electrical conductivity
- Giant covalent network structures have very high melting and boiling points because the network of strong covalent bonds must be broken.
- Covalent molecules tend to be insoluble in water but soluble in covalent type solvents.
- Covalent molecules never conduct except carbon graphite.
102
How are Ionic bonds held together?
the electrostatic attraction between positive and negative ions.
103
What is the formula for:
Sulphur Monoxide
Carbon Dichloride
Copper Tribromide
Phosphorus Tetrahydride
SO
CCl2
CuBr3
PH4
104
What is the formula of strontium chloride?
Sr Cl
2 1
1 2
SrCl2
105
What is the formula of Germanium sulfide?
Ge S
4 2
2 4
1 2
GeS2
106
How can you find out the valency of group ions?
We can take the number of charges on the ion as the valency of the ion.
OH- has a valency of 1
SO42- has a valency of 2
107
What is the formula of Magnesium Carbonate?
Mg Co3
2 2
2 2
1 1
MgCo3
108
Work out the formula of Beryllium Phosphate.
Be Po4
2 3
3 2
Be3(Po4)2
109
What is the formula of:
Copper (II) chloride?
Copper (I) chloride?
CuCl2
CuCl
110
What is the ionic formula for potassium nitrate?
Potassium makes 1 bond and will be positive.
Nitrate makes 1 bond and has a negative charge (from data booklet)
Formula = KNO3
Ionic formula = K+NO3-
111
What is the ionic formula for iron(III) oxide?
Iron makes 3 bonds and will be positive
Oxygen makes 2 bonds and will be negative
Formula = Fe2O3
Ionic formula = (Fe3+)2(O2-)3
112
What is meant by the gram formula mass (GFM) of a substance?
The GFM is the mass of one mole of a substance.
113
How do you calculate the Gram Formula Mass (GFM) of a compound?
Work out the formula then add all the mass numbers together.
114
What is the GFM of Carbon Dioxide?
CO2
12 + (2x16) = 44
115
How many moles are present in 25 g of calcium carbonate? (GFM=100)
number of moles = mass/GFM
25/100 = 0.25 moles
116
Calculate the mass of 0.25 moles of butane (C4H10)
RAM of Carbon = 12
RAM of Hydrogen = 1
mass = number of moles x GFM
mass = 0.25 x 58
mass = 14.5g
117
How many of moles in 400cm3 of 0.2 mol l-1 sodium hydroxide (NaOH) solution.
Number of moles = concentration x volume
Convert volume to litres by dividing by 1000
= 0.2 x 0.4
= 0.08 moles
118
Calculate the concentration of the solution formed when 0.75 moles of sodium chloride are dissolved in 500 cm3 of water.
Concentration = number of moles/volume.
Convert volume into litres by dividing by 1000.
Concentration = 0.75/0.5
Concentration = 1.5 mol l-1
119
Calculate the volume of sodium hydroxide used in 0.6 mol l-1 solution containing 1.2 mol of solute.
Volume = number of moles / concentration
= 1.2 / 0.6
= 2 litres
120
Equations can be described as being balanced. What does this mean?
A chemical equation is said to be balanced when there are the same number of the same type of every atom on both sides of the equation.
121
How can you balance an equation?
Balancing is adding BIG numbers. You cannot change any of the small numbers in a chemical formula. If balancing is required, put the number in front of the substance.
122
How would this equation be balanced?
Cu + 2O→ CuO
2Cu + 2O → 2CuO
123
Balance this equation
C4H8 + O2 → CO2 + H2O
Balance Carbons
C4H8 + O2 → 4CO2 + H2O
Balance Hydrogens
C4H8 + O2 → 4CO2 + 4H2O
Balance Oxygens
C4H8 + 6O2 → 4CO2 + 4H2O
124
How large is the pH scale?
- 2 to 14
125
How can pH be measured?
Using indicators such as pH paper or universal indicator.
126
What are the different kinds of pH can you have?
Acids, Neutral, Alkali
127
State some facts about acids and alkalis.
- Alkalis are water soluble bases
- Bases are metal oxide, metal hydroxides and metal carbonates
- Acids are made by dissolving non - metal oxides in water
- Alkalis are made by dissolving metal oxides in water
128
What do common lab acids contain?
Hydrogen
129
What happens when water molecules ionise?
Hydrogen and hydroxide ions are produced.
130
What do these arrows mean? ___\
\----
Reversible action
131
What does this mean? [ ]
Concentration
132
What do these mean?
[ ] > [ ]
[ ] = [ ]
[ ] < [ ]
Greater concentration
Equal concentration
Less concentration
133
State 3 things about diluting acids and alkalis.
- Adding water decreases concentration of acids and alkalis.
- When acids are diluted pH increases until it becomes neutral and reaches 7
- When alkalis are diluted pH decreases until it becomes neutral or reaches 7
134
What is neutralisation?
The reaction of acids with bases.
135
What is alkali?
A base which dissolves in water.
136
Acid + Base =
Salt + Water
137
Give some examples of bases.
metal hydroxides
metal carbonates
metal oxides
ammonia
138
Give some examples of bases that can form an alkali.
copper (II) oxide
calcium oxide
139
How to name the salt in:
acid + base = salt + water
- The first part comes from the metal in the alkali or base.
- The second part comes from the acid used.
140
What types of bases are soluble and alkali?
metal hydroxides
141
What types of bases are insoluble and alkali?
metal oxides
carbonates
142
What can acids be neutralised by?
metal hydroxides
metal oxides
metal carbonates
143
What do neutralisation reactions always produce?
Salt + Water
144
What are some common lab acids and their formula?
Sulfuric acid: H2So4
Hydrochloric acid: HCL
Nitric acid: HNO3
145
What does the pH of a substance tell you?
How acidic or alkaline a substance is (the pH of the substance)
146
What word is used to describe chemical with a pH of
a. Less than 7
b. exactly 7
c. More than 7
a. Acids have a pH of less than 7.
b. Water and neutral solutions have a pH of exactly 7.
c. Alkalis have a pH more than 7.
147
What is the difference between a base and an alkali?
Substances that can react with acids and neutralise them to make a salt and water are called bases.
Bases that dissolve in water are called alkalis.
148
How are acids and alkalis formed?
An alkaline solution can be formed when a metal oxide is dissolved in water.
An acidic solution can be formed when a non-metal oxide is dissolved in water.
149
What type of chemicals would have no effect on pH?
Insoluble substances will have no effect on pH.
150
Acidic and alkaline solutions can conduct electricity because they have ions that are free to carry charge.
What ion do all acids contain?
Hydrogen ion
H+
151
Acidic and alkaline solutions can conduct electricity because they have ions that are free to carry charge.
What ion do all alkalis contain?
Hydroxide ion
OH
152
Which acids are the following formulae representing?
i) HCl or H+ (aq)Cl-(aq)
ii) H2SO4 or 2H+(aq) SO42-(aq)
iii) HNO3 or H+(aq) NO3(aq)
i) Hydrochloric acid
ii) Sulphuric acid
iii) Nitric acid
153
Which alkalis are the following formulae representing?
i) NaOH or Na+ (aq) OH-(aq)
ii) Ca(OH)2 or Ca+(aq) 2OH-(aq)
iii) LiOH or Li+(aq) OH-(aq)
i) Sodium hydroxide
ii) Calcium hydroxide
iii) Lithium hydroxide
154
Water is a covalent compound. These do not conduct electricity.
Yet I was always told not to make toast in the bath.
Please explain.
No one likes soggy toast.
A very small proportion of water molecules will dissociate into an equal number of hydrogen and hydroxide ions.
H2O(l) ⇔ H+(aq) + OH-(aq)
155
How does the concentration of hydrogen ions (H+(aq)) compare to the concentration of hydroxide ions (OH-(aq)) in water and neutral solutions?
In water and neutral solutions, the concentration of hydrogen ions (H+(aq)) is equal to the concentration of hydroxide ions (OH-(aq)) .
156
How does the concentration of hydrogen ions (H+(aq)) compare to the concentration of hydroxide ions (OH-(aq)) in an alkaline solution,
In alkaline solutions, the concentration of hydroxide ions (OH-(aq) is greater than the hydrogen ion (H+(aq)) concentration.
157
How does the concentration of hydrogen ions (H+(aq)) compare to the concentration of hydroxide ions (OH-(aq)) in an acidic solution.
In acidic solutions, the concentration of hydrogen ions (H+(aq)) is greater than the hydroxide ion (OH-(aq)) concentration.
158
What is the general equation when an acid is neutralised by a metal oxide?
Acid + Metal oxide → Metal Salt + Water
