8402/1G/KL/106783/Jun15/E3(Jun158402101)

AQA Level 1/2 Certificate

June 2015

Chemistry 8402/1

Paper 1

Thursday 14 May 2015 9.00 am to 10.30 am

For this paper you must have: a ruler a calculator the periodic table (enclosed).

Time allowed 1 hour 30 minutes

Instructions Use black ink or black ball-point pen. Fill in the boxes at the top of this page. Answer all questions. You must answer the questions in the spaces provided. Do not write

outside the box around each page or on blank pages. Do all rough work in this book. Cross through any work you do not want

to be marked.

Information The marks for questions are shown in brackets. The maximum mark for this paper is 90. You are expected to use a calculator where appropriate. You are reminded of the need for good English and clear presentation in

your answers. Question 4(b)(ii) should be answered in continuous prose.

In this question you will be marked on your ability to:– use good English– organise information clearly– use specialist vocabulary where appropriate.

Advice In all calculations, show clearly how you work out your answer.

Centre Number Candidate Number

Surname

Other Names

Candidate Signature

For Examiner’s Use

Examiner’s Initials

Question Mark

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A

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Answer all questions in the spaces provided.

1 The structures of four substances, A, B, C and D, are represented in Figure 1.

Figure 1

A B C D

1 (a) Use the correct letter, A, B, C or D, to answer each question.

1 (a) (i) Which substance is a gas? [1 mark]

1 (a) (ii) Which substance is a liquid? [1 mark]

1 (a) (iii) Which substance is an element? [1 mark]

1 (a) (iv) Which substance is made of ions? [1 mark]

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1 (b) Figure 2 shows the bonding in substance C.

Figure 2

O S O

1 (b) (i) What is the formula of substance C?

Draw a ring around the correct answer.[1 mark]

SO2 SO2 S2O

1 (b) (ii) Use the correct answer from the box to complete the sentence.[1 mark]

delocalised shared transferred

When a sulfur atom and an oxygen atom bond to produce substance C,

electrons are .................................................................. .

1 (b) (iii) What is the type of bonding in substance C?

Draw a ring around the correct answer.[1 mark]

covalent ionic metallic____

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2 Five elements, V, W, X, Y and Z, are shown in the periodic table in Figure 3.

The letters are not the chemical symbols of the five elements.

Figure 3

W

V

X Y

Z

Use the correct letter, V, W, X, Y or Z, to answer each question.

2 (a) Which element is a transition metal? [1 mark]

2 (b) Which element is in Group 2? [1 mark]

2 (c) Which element is a noble gas? [1 mark]

2 (d) Which element has an atomic (proton) number of 4? [1 mark]

2 (e) Which element forms only 1+ ions? [1 mark]

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3 This question is about water.

River water needs to be treated before it is safe to drink.

3 (a) Figure 4 shows two stages of the treatment of river water.

Figure 4

River water

Solidparticlesremoved

Stage 1

Watersterilised

Stage 2

3 (a) (i) What is the name of the process used to remove solid particles in Stage 1?

Tick () one box.[1 mark]

Crystallisation

Fermentation

Filtration

3 (a) (ii) What is added in Stage 2 to sterilise the water?

Tick () one box.[1 mark]

Chlorine

Fluoride

Potassium

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3 (b) Toxic substances in river water are removed by adding very small amounts of iron oxide nanoparticles.

3 (b) (i) How is the size of nanoparticles different from normal-sized particles?[1 mark]

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3 (b) (ii) Nanoparticles are needed in only very small amounts.

Suggest why.[1 mark]

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3 (c) In certain areas of the UK, tap water contains aluminium ions.

What would you see when sodium hydroxide solution is added drop by drop to tap water containing aluminium ions?

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4 This question is about magnesium.

4 (a) (i) The electronic structure of a magnesium atom is shown in Figure 5.

Figure 5

Nucleus

Use the correct answer from the box to complete each sentence.[3 marks]

electrons neutrons protons shells

The nucleus contains protons and .................................................................................. .

The particles with the smallest relative mass that move around the nucleus

are called ..................................................................................... .

Atoms of magnesium are neutral because they contain the same number of

electrons and ..................................................................................... .

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4 (a) (ii) A magnesium atom reacts to produce a magnesium ion.

Which diagram shows a magnesium ion?

Tick () one box.[1 mark]

2 –2+ +

4 (b) Magnesium and dilute hydrochloric acid react to produce magnesium chloride solution and hydrogen.

Mg(s) + 2 HCl(aq) MgCl2(aq) + H2(g)

4 (b) (i) State two observations that could be made during the reaction.[2 marks]

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4 (b) (ii) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Describe a method for making pure crystals of magnesium chloride from magnesium and dilute hydrochloric acid.

In your method you should name the apparatus you will use.

You do not need to mention safety.[6 marks]

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5 A student investigated the rate of reaction between sodium thiosulfate solution and dilute hydrochloric acid, as shown in Figure 6.

Figure 6

Sodium thiosulfate solutionand dilute hydrochloric acid

White paper markedwith a cross

The reaction produced a precipitate, which made the mixture turn cloudy.

The student timed how long it took until she could no longer see the cross.

She calculated the rate of the reaction.

5 (a) The equation for the reaction is:

Na2S2O3(aq) + 2 HCl(aq) 2 NaCl(aq) + S(s) + SO2(g) + H2O(l)

Name the product that made the mixture go cloudy.[1 mark]

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5 (b) The student investigated the effect of changing the temperature of the sodium thiosulfate solution on the rate of reaction.

She plotted her results on a graph, as shown in Figure 7.

Figure 7

40 50 60200

20

40

60

80

100

120

140

30Temperature in °C

Relativerate ofreaction

70 80

Describe the trends shown in the student’s results.[2 marks]

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5 (c) The student then investigated the effect of changing the concentration of sodium thiosulfate solution on the rate of the reaction.

5 (c) (i) Suggest two variables the student would need to control to make sure that her results were valid.

[2 marks]

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5 (c) (ii) From this investigation the student correctly concluded:

‘As the concentration of sodium thiosulfate solution doubles, the rate of reaction doubles.’

Explain the student’s conclusion in terms of particles.[3 marks]

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6 This question is about polymers.

6 (a) The polymer polyvinyl chloride (PVC) is non-biodegradable.

Give one problem caused by non-biodegradable polymers.[1 mark]

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6 (b) Figure 8 shows a short section of a PVC molecule.

Figure 8

H

C

H

Cl

C

H

H

C

H

Cl

C

H

H

C

H

Cl

C

H

PVC is produced from a monomer that contains two carbon atoms.

Complete the structure of the monomer. [2 marks]

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6 (c) Figure 9 represents a few short chains of PVC molecules.

Figure 9

Explain why PVC softens and melts when heated.

Use Figure 9 and your knowledge of structure and bonding to help you to answer the question.

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6 (d) Monomer A and monomer B react to form polymer C.

The displayed structures of monomer A, monomer B and a short section of polymer C are shown in Figure 10. The functional group of each structure is shown in a box.

Figure 10

Monomer A Monomer B Polymer C

H O

H

C

H

H

C

H

O HO C

O

C

O

O

H HO

H

C

H

H

C

O

C

O

C

H

O

Complete Table 1 by writing the names of the functional groups for monomer A and polymer C.

[2 marks]

Table 1

Name of functional group

Monomer A...........................................................................

Monomer B alcohol

Polymer C...........................................................................

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7 This question is about copper.

7 (a) Copper can be extracted by smelting copper-rich ores in a furnace.

The equation for one of the reactions in the smelting process is:

Cu2S(s) + O2(g) 2 Cu(s) + SO2(g)

Explain why there would be an environmental problem if sulfur dioxide gas escaped into the atmosphere.

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7 (b) The impure copper produced by smelting is purified by electrolysis, as shown in Figure 11.

Figure 11

Negative electrode(cathode)pure copper

Positive electrode(anode)impure copper

Electrolyte

d.c. power supply

Copper atoms are oxidised at the positive electrode to Cu2+ ions, as shown in the half equation.

Cu(s) Cu2+(aq) + 2e–

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7 (b) (i) How does the half equation show that copper atoms are oxidised?[1 mark]

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7 (b) (ii) The Cu2+ ions are attracted to the negative electrode, where they are reduced to produce copper atoms.

Write a balanced half equation for the reaction at the negative electrode.[1 mark]

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7 (b) (iii) Suggest a suitable electrolyte for the electrolysis.[1 mark]

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7 (c) Copper metal is used in electrical appliances.

Describe the bonding in a metal, and explain why metals conduct electricity.[4 marks]

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7 (d) Soil near copper mines is often contaminated with low percentages of copper compounds.

Phytomining is a new way to extract copper compounds from soil.

Describe how copper compounds are extracted by phytomining.[3 marks]

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7 (e) A compound in a copper ore has the following percentage composition by mass:

55.6% copper, 16.4% iron, 28.0% sulfur.

Calculate the empirical formula of the compound.

Relative atomic masses (Ar): S = 32; Fe = 56; Cu = 63.5

You must show all of your working.[4 marks]

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Empirical formula = ............................................................____16

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8 This question is about iron and aluminium.

8 (a) Iron is extracted in a blast furnace. Figure 12 is a diagram of a blast furnace.

Figure 12

Coke (carbon)Limestone (calcium carbonate)Haematite (iron(III) oxide)

Waste gases

Molten ironHot airHot air

8 (a) (i) Calcium carbonate decomposes at high temperatures.

Complete the word equation for the decomposition of calcium carbonate.[2 marks]

calcium carbonate ............................................... + ...............................................

8 (a) (ii) Carbon burns to produce carbon dioxide.

The carbon dioxide produced reacts with more carbon to produce carbon monoxide.

Balance the equation.[1 mark]

C(s) + CO2(g) .......... CO(g)

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8 (a) (iii) Carbon monoxide reduces iron(III) oxide:

Fe2O3(s) + 3 CO(g) 2 Fe(s) + 3 CO2(g)

Calculate the maximum mass of iron that can be produced from 300 tonnes of iron(III) oxide.

Relative atomic masses (Ar): O = 16; Fe = 56[3 marks]

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Maximum mass = .............................. tonnes

8 (b) Aluminium is extracted by electrolysis, as shown in Figure 13.

Figure 13

Positiveelectrodes(anodes)

Negativeelectrode(cathode)

Molten aluminium

Aluminium oxidedissolved inmolten cryolite

8 (b) (i) Why can aluminium not be extracted by heating aluminium oxide with carbon?[1 mark]

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8 (b) (ii) Explain why aluminium forms at the negative electrode during electrolysis.[3 marks]

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8 (b) (iii) Explain how carbon dioxide forms at the positive electrodes during electrolysis.[3 marks]

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9 This question is about ethanol.

9 (a) Ethanol is produced by the reaction of ethene and steam:

C2H4 + H2O C2H5OH

9 (a) (i) Figure 14 shows the energy level diagram for the reaction.

Figure 14

Energy

C2H5OH

C2H4 + H2O

How does the energy level diagram show that the reaction is exothermic?[1 mark]

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9 (a) (ii) A catalyst is used for the reaction.

Explain how a catalyst increases the rate of the reaction.[2 marks]

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9 (b) Figure 15 shows the displayed structure of ethanol.

Figure 15

H

H

C

H

H

C

H

O H

Complete the dot and cross diagram in Figure 16 to show the bonding in ethanol.

Show the outer shell electrons only.[2 marks]

Figure 16

H

CH

H

H

C O

H

H

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9 (c) A student burned some ethanol.

Figure 17 shows the apparatus the student used.

Figure 17

50 g of water

Glass beaker

Thermometer

Spirit burnercontaining ethanol

9 (c) (i) The student recorded the temperature of the water before and after heating.

His results are shown in Table 2.

Table 2

Temperature before heating 20.7 °C

Temperature after heating 35.1 °C

Calculate the energy used to heat the water.

Use the equation Q = m c ∆T

The specific heat capacity of water = 4.2 J/g/°C[3 marks]

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Energy used = ........................................ J

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9 (c) (ii) Table 3 shows the mass of the spirit burner before the ethanol was burned and after the ethanol was burned.

Table 3

Mass of spirit burner before ethanol was burned 72.80 g

Mass of spirit burner after ethanol was burned 72.10 g

Calculate the number of moles of ethanol (C2H5OH) that were burned.

Relative atomic masses (Ar): H = 1; C = 12; O = 16[3 marks]

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Number of moles burned = ........................................

9 (c) (iii) Calculate the energy released in joules per mole.

You should assume that all the energy from the ethanol burning was used to heat the water.

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Energy = ........................................ J/mole

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9 (d) The names, structures and boiling points of ethanol and two other alcohols are shownin Table 4.

Table 4

Name Methanol Ethanol Propanol

Structure

H

H

C

H

O H H

H

C

H

H

C

H

O H H

H

C

H

H

C

H

H

C

H

O H

Boiling point in °C 65 78 97

Use your knowledge of structure and bonding to suggest why the boiling points increase as the number of carbon atoms increases.

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