Q1.€€€€€€€€€This question is about the structure of...

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 C

6 6

Complete the table of information for these two isotopes.

(2) (Total 5 marks)

ATOMIC NUMBER

MASS NUMBER

NUMBER OF PROTONS

NUMBER OF NEUTRONS

12 Isotope C

6 6 12 6

6

12 Isotope C

6 6 6

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)

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(b) Magnesium sulphate can be made from magnesium and dilute sulphuric acid.

This is the equation for the reaction.

Mg + H2SO

4 → MgSO

4 + H

2

Calculate the mass of magnesium sulphate that would be obtained from 4g of magnesium. (Show your working.)

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

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.....................................................................................................................................

.....................................................................................................................................

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)

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Q4. Calculate the formula mass (Mr), of the compound

calcium hydroxide, Ca (OH)2.

(Show your working)

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............................................................................................................................................

............................................................................................................................................ (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.

(3)

CALCIUM PHOSPHOROUS FLUORINE

Number of protons in the nucleus 20 9

Number of neutrons in the nucleus 20 16

Number of electrons 15 9

(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)

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(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 non-conductors, 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, Fe

2O

3.

(Show your working.)

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

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(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:

Fe2O

3 + 2Al → 2Fe + Al

2O

3

(Show your working.)

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.....................................................................................................................................

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.....................................................................................................................................

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:

13 protons and 14 neutrons.

(a) 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)

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(c) Complete the table for the element fluorine.

(3) (Total 7 marks)

PARTICLE NUMBER OF PROTONS

NUMBER OF NEUTRONS

NUMBER OF ELECTRONS

Fluorine atom 9 9

Fluoride atom 10

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 ISOTOPE 2

14 mass number 12 C C

6 proton number 6

(a) Describe two ways in which the isotopes are similar.

.....................................................................................................................................

..................................................................................................................................... (2)

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(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) NH

3(g) + HCl (g)

ammonium chloride ammonia 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)

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(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.

(2)

Name of sub-atomic particle

Relative mass Relative charge

............................... 1 +1

............................... 1 0

...............................

–1

(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.

(3)



.................................

......................

Neutron ..................... .......................

................................. 1 .......................

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(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.

Two of these elements can react together to form a chemical compound.

Name of element

Chemical symbol

Number of electrons in:

1st

shell 2nd

shell 3rd

shell

Fluorine F 2 7 0

Neon Ne 2 8 0

Sodium Na 2 8 1

(i) What is the name and the formula of this compound?

Name ................................................... Formula .......................................... (2)

(ii) What type of bonding holds this compound together?

........................................................................................................................... (1)

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(iii) Explain, in terms of electron transfer, how the bonding occurs in this compound.

...........................................................................................................................

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...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

........................................................................................................................... (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) + H

2(g)

(a) Write a balanced ionic equation for this reaction.

.................................................................................................................................... (2)

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(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 H2O

2.

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)

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Q13. Electrons, neutrons and protons are sub-atomic particles.

(a) Complete the six spaces in the following table.

(3)



....................................... 1 ........................................

....................................... ........................................ 0

.......................................

.........................................

(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)

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(e) The diagram shows part of the ionic lattice of a sodium chloride crystal.

Explain why the ions in this lattice stay in place.

....................................................................................................................................

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....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (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.

(1)

Element Number of atoms in

NH4Cl

nitrogen 1

hydrogen

chlorine

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(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)

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(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:

NH4NO

3 and KCl

(i) Use the Data Sheet to help you answer this question. Name the elements in the compound NH

4NO

3.

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 NH

4NO

3.

(Relative atomic masses: H = 1, N = 14, O = 16.)

..........................................................................................................................

.......................................................................................................................... (1)

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(ii) Use your answer to part (f)(i) to help you calculate the percentage by mass of nitrogen present in ammonium nitrate NH

4NO

3.

..........................................................................................................................

..........................................................................................................................

.......................................................................................................................... (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 slaked line

(i) 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)

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Q17. 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 .............................................................................................................

(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.

....................................................................................................................................

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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)

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(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 2.8.7

(i) Use the relevant electron arrangements to describe the bonding in water.

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(ii) Use the relevant electron arrangements to describe the bonding in sodium chloride.

...........................................................................................................................

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...........................................................................................................................

...........................................................................................................................

........................................................................................................................... (3)

(b) Use the atomic structures of and to explain the meaning of the term isotopes.

.....................................................................................................................................

.....................................................................................................................................

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.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (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, Fe2O

3.

.....................................................................................................................................

..................................................................................................................................... (1)

(ii) Step 2

Calculate the total relative mass of just the iron atoms in the formula, Fe2O

3.

..................................................................................................................................... (1)

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(iii) Step 3

Calculate the percentage (%) of iron in the iron oxide, Fe2O

3.

.....................................................................................................................................

.....................................................................................................................................

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.

.....................................................................................................................................

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.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 4 marks)

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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, NH4NO

3?

......................................................................................................................... (1)

(ii) Work out the relative formula mass of ammonium nitrate, NH4NO

3.

Relative atomic masses: H 1; N 14; O 16.

...........................................................................................................................

...........................................................................................................................

Relative formula mass of ammonium nitrate = ............................... (1)

(Total 4 marks)

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Q23. Uranium metal can be produced by reacting uranium hexafluoride with calcium.

UF6 + 3Ca → 3CaF

2 + 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, and . Use these as examples to explain what is meant by the word isotope.

.....................................................................................................................................

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(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:

Fe2O

3(s) + 3CO(g) → 2Fe(s) + 3CO

2(g)

Calculate the relative formula mass of iron oxide, Fe2O

3.

Relative atomic masses: O 16; Fe 56.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

Relative formula mass Fe2O

3 = ................................

(Total 2 marks)

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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.

.....................................................................................................................................

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.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (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.

.....................................................................................................................................

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.....................................................................................................................................

..................................................................................................................................... (4)

(Total 8 marks)

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Q26. Calcium carbonate tablets are used to treat people with calcium deficiency.

(a) Calculate the relative formula mass (Mr) 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)

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(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) →CaCl

2 (aq) + H

2O (l) + CO

2 (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, Fe2O

3.

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)

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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)

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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 (Mr) of SnF

2.

Relative atomic masses: F = 19; Sn = 119

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

Relative formula mass (Mr) = ..........................................

(2)

(b) Calculate the percentage by mass of fluorine in SnF2.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

Percentage by mass of fluorine = .......................................... % (2)

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(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 .

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(a) Calculate the relative formula mass (Mr) of SnF

2.

Relative atomic masses: F = 19; Sn = 119

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

Relative formula mass (Mr) = ..........................................

(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.

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....................................................................................................................................

Mass of fluorine = .......................................... g (1)

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(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)

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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]

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M4. Ca = 40

(OH)2 = (16 + 1)2 or 34

gain 1 mark each

but M

r = 74

gains 3 marks [3]

M5. (a)

for 1 mark each

3

Calcium Phosphorus Fluorine

No of protons 15

No of neutrons 10

No of electrons 20

(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

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(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 O

3 + 2A1 → 2Fe + A1

2 O

3]

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 Fe

2 O

3 → 32/160 × 112

gains 2 marks

but = 22.4

gains 3 marks 3

[6]

M7. (a) (i) 27

(ii) 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

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(c)

each for 1 mark

3 [7]

PARTICLE NUMBER OF PROTONS

NUMBER OF NEUTRONS

NUMBER OF ELECTRONS

Fluorine atom 10

Fluoride atom 9 10

M8. (a) reference to hydrogen (atoms) ) nitrogen (atoms) ) but not molecules

each for 1 mark

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

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(b) different number of neutrons gains 1 mark

but or

C has two more neutrons different mass number gains 1 mark

or

but two mass units bigger

gains 2 marks

C has 8 neutrons while C has 6 neutrons gains 2 marks

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

of 50

(iv) nitrogen do not credit N/N

2

1

hydrogen do not credit H/H

2

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

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

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

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 ammonia or N

2 H

2 NH

3

all correct for 1 mark 1

(c) largest area labelled nitrogen or shaded for 1 mark

1

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) NH4NO

3 = 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]

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

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

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]

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

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

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

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

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]

of 50

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