Q1.
This question is about the structure of atoms.
(a)
Choose words from the list to complete the sentences below.
electrons
ions
neutrons
protons
In an atom, the particles with a negative charge are called .....................................
Particles in the nucleus with no charge are called .....................................................
An atom has no overall charge because is has the same number of electrons and
....................................................................................................................................
(3)
(b)
Two isotopes of the element carbon are:
12
14
C
and
6
C
6
Complete the table of information for these two isotopes.
ATOMIC
NUMBER
MASS
NUMBER
NUMBER OF
PROTONS
C
6
12
6
C
6
12
Isotope
NUMBER OF
NEUTRONS
6
6
12
Isotope
6
6
(2)
(Total 5 marks)
Q2.
(a)
The formula for the chemical compound magnesium sulphate is MgSO4.
Calculate the relative formula mass (Mr)of this compound. (Show your working.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
Page 1 of 50
(b)
Magnesium sulphate can be made from magnesium and dilute sulphuric acid.
This is the equation for the reaction.
Mg
+
H2SO4
→
MgSO 4
+
H2
Calculate the mass of magnesium sulphate that would be obtained from 4g of
magnesium.
(Show your working.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
Answer..................................... g
(2)
(Total 4 marks)
Q3.
The formula for the chemical compound magnesium sulphate is MgSO4.
Calculate the relative formula mass (Mr) of this compound. (Show your working.)
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
(Total 2 marks)
Page 2 of 50
Q4.
Calculate the formula mass (Mr), of the compound
calcium hydroxide, Ca (OH)2.
(Show your working)
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
............................................................................................................................................
(Total 3 marks)
##
Atoms of calcium, phosphorus and fluorine are represented below, each with its mass
number and proton number.
(a)
Use this information to complete the table.
CALCIUM
Number of protons in the nucleus
20
Number of neutrons in the nucleus
20
Number of electrons
PHOSPHOROUS
FLUORINE
9
16
15
9
(3)
(b)
Calcium and fluorine atoms can combine to form the compound calcium fluoride, CaF2.
The fluoride ion is represented by F–.
(i)
Explain how the fluorine atom forms a fluoride ion.
..........................................................................................................................
..........................................................................................................................
(2)
(ii)
How is the calcium ion represented?
..........................................................................................................................
(2)
Page 3 of 50
(c)
Phosphorus and fluorine form a covalent compound, phosphorus trifluoride.
Complete the sentences below which are about this compound.
Phosphorus trifluoride is made up of phosphorus and fluorine ................................
These are joined together by sharing pairs of ............................................... to form
phosphorus trifluoride ........................................................ .
(3)
(d)
(i)
Sodium chloride, an ionic compound, has a high melting point whereas paraffin
wax, a molecular compound, melts easily.
Explain why.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(ii)
Molten ionic compounds conduct electricity but molecular compounds are nonconductors, even when liquid.
Explain why.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(Total 14 marks)
Q6.
The information on the Data Sheet will be helpful in answering this question.
(a)
Calculate the formula mass (Mr) of the compound iron (III) oxide, Fe2O3.
(Show your working.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
Page 4 of 50
(b)
Calculate the mass of iron produced when 32g of iron (III) oxide is completely reduced by
aluminium.
The reaction is shown in the symbol equation:
Fe2O3
+
2Al
→
2Fe
+
Al 2O3
(Show your working.)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
Answer = ..................................... grams
(3)
(Total 6 marks)
Q7.
You will find it helpful to use the information on the Data Sheet when answering this question.
In the nucleus of an aluminium atom are:
and
(a)
13 protons
14 neutrons.
Complete these sentences.
(i)
The mass number of the aluminium atom is ...................................... .
(ii)
In an atom of aluminium there are ....................................... electrons.
(2)
(b)
Why is an aluminium atom electrically neutral?
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
Page 5 of 50
(c)
Complete the table for the element fluorine.
PARTICLE
NUMBER OF
PROTONS
Fluorine atom
9
NUMBER OF
NEUTRONS
NUMBER OF
ELECTRONS
9
Fluoride atom
10
(3)
(Total 7 marks)
Q8.
(a)
The formula for ammonia is NH3. What does the formula tell you about each molecule
of ammonia?
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(b)
Ammonia is used to make nitric acid (HNO3). Calculate the formula mass (Mr) for nitric
acid. (Show your working).
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 6 marks)
Q9.
The two carbon atoms represented below are isotopes.
ISOTOPE 1
14
ISOTOPE 2
mass number
C
6
(a)
proton number
12
C
6
Describe two ways in which the isotopes are similar.
.....................................................................................................................................
.....................................................................................................................................
(2)
Page 6 of 50
(b)
Describe as fully as you can one way in which they are different.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Q10.
(a)
The equation for the reaction that takes place when ammonium chloride is heated is:
NH4Cl(s)
ammonium chloride
NH3(g)
ammonia
+
HCl (g)
hydrogen chloride
The diagram shows how a teacher demonstrated this reaction. The demonstration was
carried out in a fume cupboard.
(i)
Apart from the gases normally in the atmosphere, which two gases would be
at X?
..................................................... and ...........................................................
(1)
(ii)
Name the white solid that has formed at Y.
..........................................................................................................................
(1)
(iii)
Why was the demonstration carried out in a fume cupboard?
..........................................................................................................................
..........................................................................................................................
(1)
Page 7 of 50
(iv)
Complete the four spaces in the passage.
The chemical formula of ammonia is NH3. This shows that there is one atom of
.......................................... and three atoms of .................................. in each
......................................... of ammonia. These atoms are joined by bonds that
are formed by sharing pairs of electrons. This type of bond is called
a ............................... bond.
(4)
(b)
Electrons, neutrons and protons are sub-atomic particles.
(i)
Complete the three spaces in the table.
Name of sub-atomic
particle
Relative mass
Relative charge
...............................
1
+1
...............................
1
0
...............................
–1
(2)
(ii)
Which two sub-atomic particles are in the nucleus of an atom?
........................................................... and ...............................................
(1)
(Total 10 marks)
Q11.
(a)
Atoms are made of sub-atomic particles. Complete the six spaces in the table.
Name of sub-atomic
particle
Relative mass
.................................
Relative charge
......................
Neutron
.....................
.......................
.................................
1
.......................
(3)
Page 8 of 50
(b)
Complete the spaces in the sentences.
(i)
The atomic number of an atom is the number of ..................................... in its
nucleus and is equal to the number of ..................................................... if the
atom is not charged.
(1)
(ii)
The mass number of an atom is the total number of ................................. and
...................................... in its nucleus.
(1)
(c)
The table gives information about the atoms of three elements.
Number of electrons in:
Name of
element
Chemical
symbol
Fluorine
1st
shell
2nd
shell
3rd
shell
F
2
7
0
Neon
Ne
2
8
0
Sodium
Na
2
8
1
Two of these elements can react together to form a chemical compound.
(i)
What is the name and the formula of this compound?
Name ................................................... Formula ..........................................
(2)
(ii)
What type of bonding holds this compound together?
...........................................................................................................................
(1)
Page 9 of 50
(iii)
Explain, in terms of electron transfer, how the bonding occurs in this compound.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 10 marks)
##
In this question you will need to use the following information:
Relative atomic masses: H 1; O 16; Mg 24.
The volume of one mole of any gas is 24 dm3 at room
temperature and atmospheric pressure.
The diagram shows a chemical reaction taking place in a conical flask.
The balanced equation for this reaction is:
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
(a)
Write a balanced ionic equation for this reaction.
....................................................................................................................................
(2)
Page 10 of 50
(b)
Calculate the mass of magnesium required to produce 0.50 g of hydrogen. Show clearly
how you work out your final answer and give the unit.
.....................................................................................................................................
.....................................................................................................................................
Mass = ...............................
(2)
(c)
(i)
Draw a diagram to show how the electrons are arranged in a hydrogen molecule.
(1)
(ii)
What is the name of the type of chemical bond between the hydrogen atoms in a
hydrogen molecule?
...........................................................................................................................
(1)
(d)
The chemical formula for hydrogen peroxide is H2O2.
Calculate, to the nearest whole number, the percentage, by mass, of hydrogen in
hydrogen peroxide. Show clearly how you work out your answer.
....................................................................................................................................
....................................................................................................................................
Percentage = ................................. %
(2)
(Total 8 marks)
Page 11 of 50
Q13.
Electrons, neutrons and protons are sub-atomic particles.
(a)
Complete the six spaces in the following table.
Name of sub-atomic
particle
Relative mass
Relative charge
.......................................
1
........................................
.......................................
........................................
0
.......................................
.........................................
(3)
(b)
An aluminium atom has 13 electrons. How are these arranged in shells around the
nucleus?
....................................................................................................................................
(1)
(c)
Chromium atoms have 24 protons and 28 neutrons.
(i)
How many electrons does each neutral chromium atom have?
...........................................................................................................................
(1)
(ii)
What is the mass number of chromium?
...........................................................................................................................
(1)
(d)
What change occurs to an atom which undergoes the process of reduction in a chemical
reaction?
....................................................................................................................................
....................................................................................................................................
(1)
Page 12 of 50
(e)
The diagram shows part of the ionic lattice of a sodium chloride crystal.
Explain why the ions in this lattice stay in place.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(3)
(Total 10 marks)
Q14.
Ammonium chloride, NH4Cl, is made up of nitrogen, hydrogen and chlorine atoms.
(i)
Complete the table to show the number of atoms of each element present in NH4Cl.
Element
Number of atoms in
NH4Cl
nitrogen
1
hydrogen
chlorine
(1)
Page 13 of 50
(ii)
Calculate the relative formula mass of ammonium chloride, NH4Cl.
(Relative atomic masses: H = 1, N = 14, Cl = 35.5)
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
Relative formula mass = .................................................
(2)
(Total 3 marks)
Q15.
Ammonia is a very important chemical.
(a)
The table shows the percentage of ammonia used to make different substances.
SUBSTANCES MADE
FROM AMMONIA
PERCENTAGE (%)
OF AMMONIA USED
fertilisers
75
nitric acid
10
nylon
5
others
10
Shade on the pie chart the percentage of ammonia used to make nitric acid.
(1)
Page 14 of 50
(b)
Ammonia gas is made by the reaction between nitrogen gas and hydrogen gas.
Write a word equation to represent this reaction.
.............................. + ..............................
..............................
(1)
(c)
Nitrogen is one of the raw materials used to make ammonia.
Nitrogen is obtained from air.
This pie chart shows the proportion of nitrogen, oxygen and other gases in air.
Label the area which represents the proportion of nitrogen in air.
(1)
(d)
An artificial fertiliser contains compounds with the formulae:
NH4NO3 and
(i)
KCl
Use the Data Sheet to help you answer this question.
Name the elements in the compound NH4NO3.
1 ..........................................................
2 ..........................................................
3 ..........................................................
(2)
(ii)
Use the Data Sheet to help you answer this question.
Name the compound KCl.
..........................................................................................................................
(1)
(e)
(i)
Ammonium nitrate is one type of artificial fertiliser.
Calculate the relative formula mass of ammonium nitrate NH4NO3.
(Relative atomic masses: H = 1, N = 14, O = 16.)
..........................................................................................................................
..........................................................................................................................
(1)
Page 15 of 50
(ii)
Use your answer to part (f)(i) to help you calculate the percentage by mass of
nitrogen present in ammonium nitrate NH4NO3.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(Total 9 marks)
Q16.
Quicklime can be converted to slaked lime. The equation which represents this reaction is
shown below.
CaO(s) + H2O(l) → Ca(OH)2(s)
quickline
(i)
slaked line
Why do farmers sometimes add slaked lime to acidic soil?
.....................................................................................................................................
.....................................................................................................................................
(1)
(ii)
Use these relative atomic masses: H = 1; O = 16; Ca = 40
to calculate the relative formula mass (M r) of
quicklime CaO ...........................................................................................................
slaked lime Ca(OH)2 ..................................................................................................
(2)
(iii)
Calculate the mass of slaked lime that could be made from 1000 kg of quicklime.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
Mass of slaked lime .................... kg
(2)
(Total 5 marks)
Page 16 of 50
Q17.
Use these relative atomic masses: H = 1; O = 16; Ca = 40
to calculate the relative formula mass (Mr ) of
quicklime CaO ......................................................................................................................
slaked lime Ca(OH)2 .............................................................................................................
(Total 2 marks)
Q18.
Limestone (CaCO3) is a raw material. On strong heating it is converted to calcium oxide
which is a very useful substance.
(a)
Calculate the formula mass (Mr) of calcium carbonate.
.....................................................................................................................................
Mr of calcium carbonate = ...............................................
(2)
(b)
About 60 million tonnes of calcium oxide is made in Britain each year.
Calculate the mass of calcium carbonate needed to make this amount of calcium oxide.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Mass of calcium carbonate needed = .............................. million tonnes
(4)
(c)
Water is added to some of the calcium oxide produced in a process known as ‘slaking’.
The product of this reaction is used to make plaster.
CaO(s) + H2O(1)→ Ca(OH)2(s)
(i)
Give the chemical name of Ca(OH)2.
..........................................................................................................................
(1)
Page 17 of 50
(ii)
What is the physical state of the Ca(OH)2 formed in the reaction?
..........................................................................................................................
(1)
(Total 8 marks)
Q19.
Brine, a solution containing sodium chloride in water, can be used to manufacture chlorine,
hydrogen and sodium hydroxide. A student sets up a simplified model of the industrial cell.
(a)
The electron arrangements of some atoms are shown here.
H
1
O
2.6
Na
2.8.1
C1
(i)
2.8.7
Use the relevant electron arrangements to describe the bonding in water.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
Page 18 of 50
(ii)
Use the relevant electron arrangements to describe the bonding in sodium chloride.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(b)
Use the atomic structures of
and
to explain the meaning of the term isotopes.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 8 marks)
Q20.
Follow the steps to find the percentage of iron in iron oxide.
Relative atomic masses: O 16; Fe 56.
(i)
Step 1
Calculate the relative formula mass of iron oxide, Fe2O3.
.....................................................................................................................................
.....................................................................................................................................
(1)
(ii)
Step 2
Calculate the total relative mass of just the iron atoms in the formula, Fe2O3.
.....................................................................................................................................
(1)
Page 19 of 50
(iii)
Step 3
Calculate the percentage (%) of iron in the iron oxide, Fe2O3.
.....................................................................................................................................
.....................................................................................................................................
Percentage of iron ................................. %
(1)
(Total 3 marks)
Q21.
The diagrams show three isotopes of potassium.
(i)
In what way does the atomic structure show you that they are all atoms?
.....................................................................................................................................
.....................................................................................................................................
(1)
(ii)
Explain why these three atoms are called isotopes of potassium.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 4 marks)
Page 20 of 50
Q22.
As the world population increases there is a greater demand for fertilisers.
(a)
Explain what fertilisers are used for.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(b)
The amount of nitrogen in a fertiliser is important.
(i)
How many nitrogen atoms are there in the formula, NH4NO3?
.........................................................................................................................
(1)
(ii)
Work out the relative formula mass of ammonium nitrate, NH4NO3.
Relative atomic masses: H 1; N 14; O 16.
...........................................................................................................................
...........................................................................................................................
Relative formula mass of ammonium nitrate = ...............................
(1)
(Total 4 marks)
Page 21 of 50
Q23.
Uranium metal can be produced by reacting uranium hexafluoride with calcium.
UF6 + 3Ca → 3CaF2 + U
(a)
Describe how calcium and fluorine bond together to form calcium fluoride. The electron
arrangement of each atom is shown.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(b)
Uranium has two main isotopes,
meant by the word isotope.
and
. Use these as examples to explain what is
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
Page 22 of 50
(c)
At the start of a reaction there was 174.5 g of uranium hexafluoride, UF6.
Relative atomic masses: F 19; U 235
(i)
Calculate the relative formula mass of uranium hexafluoride, UF6.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
Relative formula mass UF6 = .................................... g
(1)
(ii)
Calculate the mass of uranium that would be produced from 134.5 g of uranium
hexafluoride.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
Mass of uranium = .................................. g
(2)
(Total 12 marks)
Q24.
The chemical equation for the formation of iron is:
Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)
Calculate the relative formula mass of iron oxide, Fe2O3.
Relative atomic masses: O 16; Fe 56.
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
Relative formula mass Fe2O3 = ................................
(Total 2 marks)
Page 23 of 50
Q25.
There is molten rock below the Earth’s solid outer crust. The rock remains molten because
the radioactive decay of isotopes such as uranium, thorium and potassium releases heat
energy.
(i)
Explain how this released heat energy is thought to cause the recycling of rocks.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(ii)
Two isotopes of potassium are shown.
Explain what is meant by isotopes. You must include numbers of electrons, neutrons and
protons in your explanation.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 8 marks)
Page 24 of 50
Q26.
Calcium carbonate tablets are used to treat people with calcium deficiency.
(a)
Calculate the relative formula mass (M r) of calcium carbonate.
Relative atomic masses: C = 12; O = 16; Ca = 40.
.....................................................................................................................................
.....................................................................................................................................
Relative formula mass = ..............................
(2)
(b)
Calculate the percentage of calcium in calcium carbonate, CaCO3.
.....................................................................................................................................
.....................................................................................................................................
Percentage of calcium = .......................... %
(2)
(c)
Calculate the mass of calcium in each tablet.
.....................................................................................................................................
.....................................................................................................................................
Mass of calcium = .................................... g
(2)
Page 25 of 50
(d)
An unwanted side effect of this medicine is that it can cause the patient to have ‘wind’ (too
much gas in the intestine).
The equation below represents the reaction between calcium carbonate and hydrochloric
acid (the acid present in the stomach).
CaCO3 (s) + 2HCl (aq) →CaCl2 (aq) + H2O (l) + CO2 (g)
Suggest why the patient may suffer from ‘wind’.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 7 marks)
Q27.
Iron ore contains iron oxide.
(i)
Calculate the relative formula mass of iron oxide, Fe2O3.
Relative atomic masses: O = 16; Fe = 56.
.....................................................................................................................................
.....................................................................................................................................
Answer = ................................................
(2)
(ii)
Calculate the percentage by mass of iron in iron oxide.
.....................................................................................................................................
Percentage of iron = .......................................... %
(2)
(iii)
Calculate the mass of iron that could be extracted from 1000 kg of iron oxide.
Use your answer to part (c) (ii) to help you with this calculation.
.....................................................................................................................................
Mass of iron = ................................................... kg
(1)
(Total 5 marks)
Page 26 of 50
Q28.
Aluminium is a useful metal.
(a)
The atomic number (proton number) of aluminium is 13.
Complete the diagram to show the electronic structure of an aluminium atom.
Use crosses (x) to represent the electrons.
(1)
(b)
Aluminium is used as the electrical conductor for overhead power cables.
Explain why metals are good conductors of electricity.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(Total 3 marks)
Page 27 of 50
Q29.
Toothpastes often contain fluoride ions to help protect teeth from attack by bacteria.
Some toothpastes contain tin(II) fluoride.
This compound has the formula SnF2 .
(a)
Calculate the relative formula mass (M r) of SnF2.
Relative atomic masses: F = 19; Sn = 119
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Relative formula mass (M r) = ..........................................
(2)
(b)
Calculate the percentage by mass of fluorine in SnF2.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Percentage by mass of fluorine = .......................................... %
(2)
Page 28 of 50
(c)
A tube of toothpaste contains 1.2 g of SnF2.
Calculate the mass of fluorine in this tube of toothpaste.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Mass of fluorine = .......................................... g
(1)
(d)
The diagram represents the electron arrangement of a fluorine atom.
Explain how a fluorine atom can change into a fluoride ion, F–.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(Total 7 marks)
Q30.
Toothpastes often contain fluoride ions to help protect teeth from attack by bacteria.
Some toothpastes contain tin(II) fluoride.
This compound has the formula SnF2 .
Page 29 of 50
(a)
Calculate the relative formula mass (M r) of SnF2.
Relative atomic masses: F = 19; Sn = 119
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Relative formula mass (M r) = ..........................................
(2)
(b)
Calculate the percentage by mass of fluorine in SnF2.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Percentage by mass of fluorine = .......................................... %
(2)
(c)
A tube of toothpaste contains 1.2 g of SnF2.
Calculate the mass of fluorine in this tube of toothpaste.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
Mass of fluorine = .......................................... g
(1)
Page 30 of 50
(d)
The diagram represents the electron arrangement of a fluorine atom.
Explain how a fluorine atom can change into a fluoride ion, F–.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
(Total 7 marks)
Page 31 of 50
M1.
(a) electrons
neutrons
protons
for 1 mark each
3
(b)
mass number
no. of neutrons
14
8
for 1 mark each
2
[5]
M2.
(a)
Mg
S
O4
24 + 32 + 16 (×4) or 64 / evidence of all Ar’s
gains 1 mark
but (Mr) = 120
gains 2 marks
2
(b)
evidence that 24(g) magnesium would produce 120(g) mapesiurn sulphate
gains 1 mark
or correct scaling by 1/6
but 20(g) magnesium sulphate
gains 2 marks
[credit error carried forward from (a) with full marks in (b)]
2
[4]
M3.
Mg
S
O4
24 + 32 + 16 (×4) or 64 / evidence of all Ar’s correct [so 24 + 32 + 16 1 mark]
gains 1 mark
but (Mr) = 120
No ECF
gains 2 marks
[2]
Page 32 of 50
M4.
Ca = 40
(OH)2 = (16 + 1)2 or 34
gain 1 mark each
but
Mr = 74
gains 3 marks
[3]
M5.
(a)
Calcium
Phosphorus
No of protons
15
No of neutrons
No of electrons
Fluorine
10
20
for 1 mark each
3
(b)
(i)
gain of electron(s)
from (atoms) (of) calcium
for 1 mark
2
(ii)
Ca+
gains 1 mark
but superscript only Ca2+ / Ca ++
gains 2 marks
2
(c)
atoms
electrons
molecule(s)
not compound
each for 1 mark
3
(d)
(i)
ideas that
•
ionic – strong forces between ions
•
molecular – weak forces between molecules
each for 1 mark
2
Page 33 of 50
(ii)
ideas that
•
ionic – ions/charged particles are free to move
•
molecular -molecules do not carry a charge
each for 1 mark
2
[14]
##
(a)
Fe2 [56 × 2] or 112
O3 [16 × 3] or 48
each gain 1 mark
but Mr = 160
gains 3 marks
3
(b)
[Fe2 O3 + 2A1 → 2Fe + A12 O3]
160 → 112 (NB Credit if unworked
(or value
(or value but should be totalled)
from (a))
from (a))
gains 1 mark
but
32 g. of Fe2 O3 → 32/160 × 112
gains 2 marks
but = 22.4
gains 3 marks
3
[6]
M7.
(a)
(ii)
(i)
27
13
each for 1 mark
2
(b)
each proton has a/1 positive charge and each electron has a/1 negative
charge OR electrons and protons have (equal but) opposite charges
there are equal numbers of protons and electrons in the atom/
so charges cancel or balance (each other)
each for 1 mark
2
Page 34 of 50
(c)
PARTICLE
NUMBER OF
PROTONS
Fluorine atom
Fluoride atom
NUMBER OF
NEUTRONS
NUMBER OF
ELECTRONS
10
9
10
each for 1 mark
3
[7]
M8.
(a) reference to
hydrogen (atoms)
)
nitrogen (atoms)
)
each for 1 mark
but not molecules
ratio of 1N to 3H atoms
for 1 further mark
or 1 nitrogen atom and 3 hydrogen atoms
(ignore any incorrect statements about nature of bonding)
3
(b)
evidence of
H=1
N = 14
O = 16
gains 1 mark
but
H=1
N = 14
O = 16 × 3 or 48
gains 2 marks
but 63
gains 3 marks
3
[6]
M9.
(a) same number/six electrons;
same number/six protons;
react in same way not same element or both carbon
any two for 1 mark each
2
Page 35 of 50
(b)
different number of neutrons
gains 1 mark
but
C
or
has two more neutrons
gains 1 mark
different mass number
or
but two mass units bigger
gains 2 marks
C
has 8 neutrons while
gains 2 marks
C
has 6 neutrons
2
[4]
M10.
(a)
(i)
ammonia and hydrogen chloride
both required either order
accept formulae if correct in every detail
1
(ii)
ammonium chloride / NH4Cl
do not credit ammonia chloride
1
(iii)
the fumes / gases / are poisonous / toxic
or ammonia and hydrogen chloride are
poisonous / toxic / lethal
accept just ammonia is poisonous / toxic
accept just hydrogen chloride is
poisonous / toxic
accept vapour is poisonous / toxic
do not credit just fumes are dangerous
or harmful
1
Page 36 of 50
(iv)
nitrogen
do not credit N/N2
1
hydrogen
do not credit H/H2
1
molecule
do not credit compound or mole
1
covalent
accept single / molecular
1
(b)
(i)
proton
neutron
electron
either all three correct
or one or two correct
however do not credit a response
which is repeated
2
(ii)
protons and neutrons
both required in either order
1
[10]
M11.
(a)
both correct in each row
electron ...– (1)
allow negative
1
1 .......... 0
allow neutral or none
1
proton .....+ (1)
allow positive
1
(b)
(i)
protons...electrons
both correct in correct order
1
(ii)
protons....neutrons
both correct in either order
1
Page 37 of 50
(c)
(i)
sodium fluoride
do not credit sodium fluorine
1
NaF
must be correct in every detail
do not credit NAF and the like
1
(ii)
ionic
accept ion (bonding)
do not credit ironic or iron (bonding)
1
(iii)
electron transferred from sodium to fluorine
accept electron transferred from metal to non-metal
either positive sodium ion and negative fluoride ion
or correctly identified by the symbols Na+ and F- accept ‘positive
sodium ion and negative fluorine ion’
1
or attracted because have opposite charge(s)
or (atoms/ions) form an (ionic) lattice or (atoms/ions) form a
crystal
e.g.
or both marks may be gained by a suitable dot and cross diagram
1
[10]
M12.
(a)
Mg + 2H+ → Mg2+ + H2
* reactants correct in every detail
* products correct in every detail
if the spectator ions are sown then (1) mark should be credited but
only if they are shown correctly on both sides
e.g.
Mg + 2H+ + 2CI- → Mg2+ + 2CI- + H2
2
(b)
24 (parts) of magnesium → 2 (parts)
1
of hydrogen or equally clear working (so) 6 grams/g (are needed)
1
unit required
Page 38 of 50
(c)
(i)
two (and no more) atoms shown to be sharing their single electrons
examples
do not credit if anything which contradicts the impression that these
are hydrogen atoms
1
(ii)
(single) covalent (bond)
1
(d)
(×100) = 6 (just 6 is worth (1) mark)
1
× 100 = 6 or similar is (0)
do not credit 5.8823529 and the like
1
[8]
M13.
(a)
proton + (1)
both required
neutron 1
both required
electron – (1)
both required
3
(b)
2.8.3
accept words or diagram to this effect
1
(c)
(i)
24
1
(ii)
52
1
(d)
any one of
•
gains one or more electrons
accept gains an electron
•
becomes an anion
do not credit becomes an ion
•
becomes a negative ion
1
Page 39 of 50
(e)
sodium ions have a (single) positive
charge and chloride ions have a
(single) negative charge
do not credit ‘chlorine ions’ but
allow this error to be carried forward
1
ions with opposite charge are
attracted (to each other)
or the positive ions and the negative ions are attracted (to each
other)
or the sodium ions and the chloride ions are attracted (to each
other)
1
(positive and negative) ions are
arranged alternatively (in each
direction or dimension)
or ions with the same charge are repelled (by each other) no mark
for just ionic bonds
1
[10]
M14.
(i)
4 and 1
both answers must be correct
1
(ii)
53.5
if incorrect relative formula mass
allow 1 mark for correct working
accept e.c.f. from c(i) for 2 marks
2
[3]
M15.
(a)
plot correct (2 segments)
for 1 mark
1
(b)
nitrogen + hydrogen
or N2
H2
ammonia
NH3
all correct for 1 mark
1
(c)
largest area labelled nitrogen or shaded
for 1 mark
1
Page 40 of 50
(d)
(i)
nitrogen
1
oxygen
hydrogen
1
three correct for 2 marks
two correct for 1 mark
(ii)
potassium chloride
for 1 mark
1
(e)
(i)
NH4NO3 = 14 + (4 × 1) + 14 + (3 × 16) = 80
for one mark
1
(ii)
ecf (error carried forward from part (i))
look for 28 / 80 for first mark
gains 1 mark
but 35% (% sign not needed)
special case of (14 / 80 × 100 = 17.5%) gains 1 mark
gains 2 marks
2
[9]
M16.
(i)
neutralise (the acid) / reduce acidity / because it is alkaline /increases pH
for 1 mark
1
(ii)
CaO = 56
Ca(OH)2 = 74
each for 1 mark
2
(iii)
mass = 1000 × 74/56
gains 1 mark
= 1321 kg (1320 accepted)
gains 2 marks
(error carried forward from (ii))
56g → 74g
1 g → 74/5 6 g (1 mark)
2
[5]
Page 41 of 50
M17.
56
74
each for 1 mark
[2]
M18.
(a)
40 + 12 + (3 × 16) = 100
each for 1 mark
2
(b)
Mr of CaO = 56
for 1 mark
mass required = 60 × 100/56
for 2 marks
= 107.1
for 1 mark
4
(c)
(i)
calcium hydroxide
1
(ii)
solid
1
[8]
M20.
(i)
160
ignore units
1
(ii)
112
ignore units
1
(iii)
70
do not carry forward errors
1
[3]
M21.
(i)
same number of protons and electrons
accept equal numbers of protons and electrons
do not accept they are neutral
1
Page 42 of 50
(ii)
same element
accept all atoms are potassium
1
same number of protons
accept same atomic number
accept they all have 19+
1
different number of neutrons
accept different mass numbers
do not accept different atomic masses
1
[4]
M22.
(a)
put on soil or for plants
accept land or field or garden or crops or plants
accept alternative answer to provide more food for increased
population
for growth
accept to improve plant yield or help them grow
accept to replace or add nutrients (not nitrates) or minerals
or to make plants grow better or for healthy plants
do not accept to make soil fertile or to feed plants
2
(b)
(i)
2
1
(ii)
80
1
[4]
M23.
(a)
calcium atom loses two electrons
accept diagrams with correct labelling
1
(each) fluorine atom gains one electron
accept two electrons transfer from a calcium atom to the two
fluorine atoms for these first two marks
1
Page 43 of 50
forming full (outer) shells of electrons
accept forming full (outer) energy levels or noble gas electronic
structures
do not accept stable unless qualified
1
giving the ions Ca2+ and F−
1
attraction between ions of opposite charges
accept electrostatic attraction between ions
if candidate mentions sharing or pairing of electrons then no credit
if explanation is entirely correct but they state this is called
covalent bonding, the maximum mark is four
1
(b)
atoms of the same element
1
atomic number is same
accept each contains 92 or same number of protons
1
mass numbers differ or each has a different number of neutrons
1
one has 146 neutrons the other has 143 neutrons
accept one has three more or less neutrons than the other
1
(c)
(i)
349
1
(ii)
349g UF2 produces 235g U [1]
first mark can be awarded if answer is incorrect
answer = 117.5
1
[12]
M24.
160
ignore units if answer incorrect then (2 × 56) + (3 × 16)
or
112 + 48 for one mark
[2]
Page 44 of 50
M25.
(i)
convection currents
accept a suitable description of convection currents
1
move the Earth’s plates
accept a suitable description of ‘movement’ of Earth’s plates
1
at plate boundary one plate or a slab of rock can be pushed down forming
magma/molten rock
accept at subduction zones magma/molten rock is formed –
deconstructive boundary
1
magma/molten rock rising and cooling at the Earth’s surface reforms
as part of the plate
accept magma/molten rock rising and cooling at the Earth’s
surface forms igneous rock – constructive boundary
accept Earth’s crust or lithosphere for Earth’s surface
1
(ii)
isotopes are atoms of the same element
do not accept that isotopes have the same atomic number but a
different atomic mass
1
19/the same number of protons
1
19/the same number of electrons
do not penalise for incorrect
1
20 and 21 neutrons/different numbers of neutrons
arithmetic if concept is correct
1
[8]
M26.
(a)
100
ignore units
40 + 12 + (3 × 16) for 1 mark
1
(b)
40
(ecf from part (a) can get 2 marks)
for 1 mark
1
Page 45 of 50
(c)
0.5
(ecf from part (b) can get 2 marks)
or other correct working for 1 mark
2
(d)
gas produced or carbon dioxide / CO2 produced
1
[7]
M27.
(i)
160 ignore units
(2 × 56) + (3 × 16) for 1 mark
2
(ii)
70
for 1 mark
allow ecf from part (i)
2
(iii)
700
allow ecf from part (ii)
1
[5]
M28.
(a)
2.8.3 on diagram as Xs / dots
or e
accept paired or unpaired
1
Page 46 of 50
(b)
any two from:
•
electrons in highest energy level or electrons in outer shell
•
electrons are delocalised or sea of electrons
•
electrons are free or electrons move around / flow
•
electrons carry charge / current
ignore carry electricity
2
[3]
M29.
(a)
157
correct answer with or without working
(2 × 19 + 119) for 1 mark only
allow (119 + 19 =) 138 for 1 mark only
ignore units
2
(b)
24.2
accept answers in the range 24 to 24.2038.....
ignore incorrect rounding after correct answer
25 only without working gains 1 mark or
38/157 × 100 gains 1 mark or
(19/157 × 100 =) 12 to 12.1 gains 1 mark
allow error carried forward from part(a)
38/(a) × 100 gains 2 marks if calculated correctly
(19/138 × 100 =) 13.8 gains 1 mark
2
(c)
0.29
accept answers in the range 0.28 to 0.3
allow error carried forward from part (b)
(b)/100 × 1.2 correctly calculated
ignore units
1
Page 47 of 50
(d)
an electron
allow electrons
allow electron shared / lost for 1 mark
apply list principle for additional particles
1
is gained owtte
must be linked to electron
accept can hold / take in if in correct context
eg it can hold another electron (in its outer shell) = 2 marks
it can take an electron (from another atom) = 2 marks
ignore reference to fluoride ions
incorrect number of electrons gained does not gain the second
mark
1
[7]
M30.
(a)
157
correct answer with or without working
(2 × 19 + 119) for 1 mark only
allow (119 + 19 =) 138 for 1 mark only
ignore units
2
(b)
24.2
accept answers in the range 24 to 24.2038.....
ignore incorrect rounding after correct answer
25 only without working gains 1 mark or
38/157 × 100 gains 1 mark or
(19/157 × 100 =) 12 to 12.1 gains 1 mark
allow error carried forward from part(a)
38/(a) × 100 gains 2 marks if calculated correctly
(19/138 × 100 =) 13.8 gains 1 mark
2
(c)
0.29
accept answers in the range 0.28 to 0.3
allow error carried forward from part (b)
(b)/100 × 1.2 correctly calculated
ignore units
1
Page 48 of 50
(d)
an electron
allow electrons
allow electron shared / lost for 1 mark
apply list principle for additional particles
1
is gained owtte
must be linked to electron
accept can hold / take in if in correct context
eg it can hold another electron (in its outer shell) = 2 marks
it can take an electron (from another atom) = 2 marks
ignore reference to fluoride ions
incorrect number of electrons gained does not gain the second
mark
1
[7]
Page 49 of 50
Page 50 of 50