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C4 Chemical Changes35 Questions

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Class: ________________________

Date: ________________________

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Page 1 of 127Brookvale Groby Learning Trust

The pH scale is a measure of the acidity or alkalinity of a solution.

(a) Draw one line from each solution to the pH value of the solution.

Solution pH value of the solution

5

Acid 7

9

Neutral 11

13

(2)

1

(b) Which ion in aqueous solution causes acidity?

Tick one box.

H+

Na+

O2−

OH−

(1)


(c) When sulfuric acid is added to sodium hydroxide a reaction occurs to produce twoproducts.

The equation is:

H2SO4 + 2NaOH Na2SO4 + 2H2O

How many elements are in the formula H2SO4?

Tick one box.

3

4

6

7

(1)

(d) What is this type of reaction?

Tick one box.

Decomposition

Displacement

Neutralisation

Reduction

(1)

(e) Name the salt produced.

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(1)


(f) Describe how an indicator can be used to show when all the sodium hydroxide has reactedwith sulfuric acid.

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(3)

(Total 9 marks)

Some students investigated the reactivity of four unknown metals, W, X, Y and Z.

The letters are not the symbols of these elements.

The students used metal salt solutions of copper nitrate, magnesium sulfate and zinc chloride.

This is the method used.1. Pour a solution of a metal salt into a glass beaker.2. Measure the temperature of the solution.3. Add 1 g of metal to the solution.4. Measure the temperature of the solution.5. Calculate the temperature increase.

The students did the experiment using each salt solution with each metal.

Figure 1 shows the apparatus the students used.

Figure 1

2


The table below shows the students’ results.

Temperature increase in °C

Solution Metal W Metal X Metal Y Metal Z

Copper nitrate 46 10 29 No change

Magnesium sulfate No change No change No change No change

Zinc chloride 15 No change No change No change

(a) Which metal is least reactive?

Tick one box.

Metal W

Metal X

Metal Y

Metal Z

(1)

(b) How do the results show that magnesium is more reactive than the metals W, X, Y and Z?

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(1)

(c) How do the results show that the reaction between metal Y and copper nitrate solution isexothermic?

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(1)


(d) One student said that the investigation was not valid (a fair test).

Write a plan for the investigation that includes improvements to the method and apparatus.

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(4)


(e) Figure 2 shows the reaction profile of an exothermic reaction.

Figure 2

What does the energy value of 1370 kJ represent?

Tick one box.

Activation energy

Products energy

Reactants energy

Released energy

(1)

(f) The overall energy change is 386 kJ.

What percentage of 1370 kJ is this?

Give your answer to two significant figures.

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Percentage = ___________________ %

(2)

(Total 10 marks)


This question is about making copper salts.

The figure below shows the apparatus given to a student.

Outline a safe plan the student could use to make pure, dry, crystals of the soluble salt coppersulfate from the insoluble metal oxide and dilute acid.

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(Total 6 marks)

3


The figure below shows an apparatus to produce elements from a solution of an ionic compound.

(a) What is the name of the process in the figure?

Tick one box.

Combustion

Crystallisation

Distillation

Electrolysis

(1)

4


(b) The table below shows the products formed from three experiments using differentcompounds and the apparatus shown in the figure above.

Compound State Product atcathode

Product at anode

Copper chloride Molten Copper Chlorine

Copper chloride Aqueous solution Copper Chlorine

Potassiumbromide

Molten Potassium Bromine

Use the table above to name the products formed at each electrode if using an aqueoussolution of potassium bromide.

At cathode __________________________ At anode _______________________

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(2)

(c) Explain why copper is formed at the cathode during the electrolysis of its salts.

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(2)

(Total 5 marks)


This question is about calcium.

(a) What type of compound is calcium oxide?

Tick one box.

An acid

A base

A carbonate

A salt

(1)

5

(b) Ionic compounds, such as calcium oxide, have high melting points.

Complete the sentences. Use words from the box.

bonds forces ions layers

Calcium oxide has a giant ionic lattice in which there are strong electrostatic

______________________ of attraction in all directions.

(1)


(c) The figure below shows the electronic structure of an oxygen atom and a calcium atom.

Describe how the calcium atom and the oxygen atom forms calcium oxide.

You should give the charge on each ion formed.

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(4)

(Total 6 marks)


Figure 1 shows a reactor used to produce titanium from titanium(IV) chloride.

Figure 1

The chemical equation for the reaction of titanium(IV) chloride with sodium is:

TiCl4 + 4Na Ti + 4NaCl

titanium(IV) chloride + sodium titanium + sodium chloride

(a) For one reaction:

• 1615 kg titanium(IV) chloride reacted completely with 782 kg sodium• 1989 kg sodium chloride was produced.

Calculate the mass of titanium produced from this reaction.

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Mass of titanium = _________________ kg

(1)

6


(b) The table below shows the solubility of sodium chloride in 100 cm3 of aqueous solution atdifferent temperatures.

Solubility of sodium chloride in g per100cm3

Temperature in °C

35.72 10

35.89 20

36.09 30

37.37 40

36.69 50

37.04 60

On Figure 2:

• plot this data on the grid• draw a line of best fit.

Figure 2

(3)


(c) The product sodium chloride is dissolved in water to separate it from titanium.

At 30 °C the solubility of sodium chloride is 36 kg per 100 dm3.

Calculate the minimum volume of water in dm3, at 30 °C, needed to dissolve 1989 kgsodium chloride.

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Volume of water = ____________________ dm3

(2)

(d) Calculate the percentage by mass of titanium in titanium(IV) chloride (TiCl4).

Give your answer to 3 significant figures.

Relative atomic masses (Ar): Cl = 35.5; Ti = 48

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Percentage of titanium by mass = _______________ %

(3)

(e) Suggest why the reaction is done in an atmosphere of dry argon instead of air containingwater vapour.

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(3)


(f) Explain why titanium conducts electricity.

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(3)

(Total 15 marks)

Copper can be produced from copper(II) sulfate solution by two different methods.

Method 1 – Electrolysis

(a) To produce copper by electrolysis a student has inert electrodes, a d.c. power supply, aswitch and electrical wires for the external circuit.

Draw and label the apparatus set up to produce copper from copper(II) sulfate solution byelectrolysis.

(2)

7

(b) Suggest why the colour of the copper(II) sulfate solution fades during the electrolysis.

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(3)


(c) Explain how copper is produced from copper(II) sulfate solution by electrolysis.

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(4)

Method 2 – Displacement

(d) The chemical equation for the displacement of copper using iron is:

CuSO4 + Fe Cu + FeSO4

Calculate the minimum mass of iron needed to displace all of the copper from 50 cm3 ofcopper(II) sulfate solution.

The concentration of the copper(II) sulfate solution is 80 g CuSO4 per dm3.

Relative atomic masses (Ar): O = 16; S = 32; Fe = 56; Cu = 63.5

Give your answer to 2 significant figures.

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Mass of iron = __________________ g

(4)

(Total 13 marks)


Hydrogen chloride (HCl) is a gas.

(a) Complete the diagram to show all of the arrangement of the outer shell electrons of thehydrogen and chlorine atoms in hydrogen chloride.

(1)

8

(b) Hydrochloric acid is a strong acid.Ethanoic acid is a weak acid.

Describe a reaction that could be used to show the difference between a weak acid and astrong acid.

You should explain why the weak acid and the strong acid give different results.

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(6)

(Total 7 marks)


Exothermic reactions transfer energy to the surroundings.

(a) Draw a reaction profile for an exothermic reaction using the axes in Figure 1.

Show the:

• relative energies of the reactants and products• activation energy and overall energy change.

Figure 1

(2)

9


(b) Combustion is an exothermic reaction.

Calculate the overall energy change for the complete combustion of one mole of methanein oxygen.

Bond Bond energy in kJ / mol

413

498

805

464

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Overall energy change = __________________ kJ / mol

(3)


(c) Figure 2 shows the chemicals given to a student.

Figure 2

The student wants to investigate the reactivity of the four metals.

Outline a plan the student could use to investigate the relative reactivity of the four metals,W, X, Y and Z.

The plan should use the fact that all four metals react exothermically with dilute sulfuricacid.

You should name the apparatus used and comment on the safe use of the chemicals.

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(6)


(d) Another student used displacement reactions to investigate the relative reactivity of the fourmetals, W, X, Y and Z.

The table below shows the student’s results.

Observations

Solution Metal W Metal X Metal Y Metal Z

Copper nitrateBrown layerformed on

metal

Brown layerformed on

metal

Brown layerformed on

metalNo change

Magnesium sulfate No change No change No change No change

Sulfuric acidGas bubbles

produced

Few gasbubbles

produced

Gas bubblesproduced

No change

Zinc chlorideGrey layerformed on

metalNo change No change No change

Give the order of reactivity of metals, W, X, Y and Z.

Use the results in the table above to justify your answer.

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(3)


(e) The student concluded that these results could also be used to justify the order of reactivityof copper, magnesium, hydrogen and zinc.

The student is not completely correct. Use the results in the table above to explain why.

Suggest one further experiment that would provide evidence for the student’s conclusion.

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(4)

(Total 18 marks)

This question is about the reactions of acids.

(a) When dilute hydrochloric acid is reacted with sodium hydroxide solution there is atemperature change.

Explain how the temperature changes.

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(2)

10


(b) Acids produce hydrogen ions in aqueous solutions.

What is the ionic equation for neutralisation reactions?

Tick one box.

H+ (aq) + H2O(l) H3O+(aq)

H+ (aq) + OH–(aq) H2O(l)

2 H2O(l) H3O+(aq) + OH–(aq)

H2O(l) 2 H+(aq) + O2–(aq)

(1)

(c) Sulfuric acid reacts with copper carbonate to produce a salt, water and carbon dioxide.

H2SO4 + CuCO3 CuSO4 + H2O + CO2

What is the name of the salt produced?

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(1)

(d) A student reacted four metals with water and with a dilute acid to work out the order ofreactivity of the metals.

The table below shows some of the observations.

Metal Reaction with water Reaction with dilute acid

Calcium Bubbles of gas X

Copper Y No bubbles of gas

Magnesium Few bubbles of gas Bubbles of gas

Zinc No bubbles of gas Bubbles of gas

Write the observations for X and Y.

Observation at X ____________________________________________________

Observation at Y ____________________________________________________

(2)


(e) Write the four metals, calcium, copper, magnesium and zinc, in order of reactivity.

Start with the most reactive metal.

_____________ _____________ _____________ ______________

(2)

(f) Some gases given off in reactions can be identified by chemical tests.

Draw one line from each chemical test to the name of the gas.

Chemical test Gas

(3)

(g) Acids react with bases to produce salts and water (H2O).

The electronic structure of a hydrogen atom is 2,1

The electronic structure of an oxygen atom is 2,6

Draw a diagram to show the arrangement of the outer shell electrons in a molecule ofwater.

(2)

(Total 13 marks)


This question is about the electrolysis of two compounds.

Figure 1 shows the electrolysis of molten lead bromide.

Figure 1

11

(a) The electrolyte contains lead ions (Pb2+) and bromide ions (Br–).

Complete the sentences.

Use words from the box.

atoms bromide bromine ions

lead molecules oxygen

At the positive electrode the gas produced is_________________________

At the negative electrode lead ____________________________________

gain electrons and ___________________ .

(3)


(b) A student measured the volumes of each gas produced during the electrolysis of water.


Time in minutesVolume of gas produced in cm3

Hydrogen Oxygen

0 0 0

2 11.2 5.4

4 20.1 11.4

6 32.5 17.6

8 40.0 23.7

10 60.9 30.0


The student plotted a graph of the results for oxygen. Figure 2 shows the graph.

The student did not put a scale on the y axis.

On the graph in Figure 2:

• complete the scale for the y axis

• plot the results for hydrogen

• include a line of best fit.

Figure 2

(3)


(c) Use the graph to calculate the mean volume of oxygen produced per second.

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Mean volume of oxygen produced = __________ cm3 / s

(3)

(Total 9 marks)

Iron is a metal that has many uses.

(a) Iron is extracted from iron ore. Part of the process involves reduction of the ore with carbonmonoxide.

Iron ore contains iron oxide (Fe2O3).

Write a balanced equation for the reaction of iron oxide with carbon monoxide.

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(3)

12

(b) Explain why this reaction is a redox reaction.

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(2)


Steel is an alloy of iron. Steel is used to make cars.

After its useful life a car is taken to a scrapyard for recycling.

(c) Suggest four benefits of recycling a car body.

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(4)


(d) Figure 1 shows an electromagnet being used to lift a car in a scrapyard.

Figure 1

An electromagnet is made up of a solenoid.

Figure 2 shows a solenoid.

Figure 2

Draw the magnetic field of the solenoid on Figure 2.

(2)


(e) In a scrapyard, an electromagnet is used to lift and release cars so they can be movedaround.

Suggest two ways a solenoid could be made to lift and release cars in a scrapyard.

Explain why each suggestion would be useful in the scrapyard.

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(4)

(Total 15 marks)

In 1869 there were 60 known elements.

Mendeleev arranged the elements in order of their atomic mass (atomic weight).

He realised that elements with similar properties occurred at regular intervals.

(a) Suggest why one of the groups that is on today’s periodic table was not in Mendeleev’speriodic system.

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(1)

13

(b) Explain the arrangement of the first 20 elements in today’s periodic table.

You should answer in terms of atomic structure.

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(2)


(c) A student put some potassium bromide solution in a test tube.

She added a few drops of chlorine solution and observed the result.

She repeated the process using different potassium halide salts and different halogens.


Solution ofhalogen

Potassiumchloride solution

Potassiumbromide solution

Potassium iodidesolution

Chlorine Orange colour

formsBrown colour

forms

Bromine No reaction Brown colour

forms

Iodine No reaction No reaction

Give the order of reactivity of the halogens from the results in the table above.

Explain how you used the results to show this order of reactivity.

Order ______________________________________________________

Explanation _______________________________________________________

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(2)

(d) Write a balanced ionic equation for the reaction of chlorine with bromide ions in solution.

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(3)


(e) Explain the order of reactivity of Group 7 elements.

Include information about atomic structure.

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(2)

(Total 10 marks)

Aluminium is produced from an ore called bauxite.

Bauxite contains aluminium oxide.

Look at Figure 1.

Figure 1

(a) Calculate the percentage of bauxite that is converted into aluminium oxide.

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Percentage = _________________

(2)

14


(b) Show by calculation that the mass of aluminium produced is less than that expected from 1950 kg aluminium oxide (Al2O3).

You should state the difference in the mass of aluminium expected and the mass ofaluminium produced to three significant figures.

Relative atomic masses (Ar): O = 16; Al = 27

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(3)

(c) Figure 2 shows an electrolysis cell used to extract aluminium.

Figure 2

Why does the carbon anode used in the electrolysis cell need to be continually replaced?

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(3)


(d) In an electrolysis cell the current is 1.5 × 105 A, at a potential difference of 4V.

Calculate the energy transferred by the electrolysis cell in 24 hours.

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Energy transferred = _________________ J

(5)

(e) The half equation at the cathode is:

Al3+ + 3 e– Al

Calculate the number of moles of electrons needed to produce 1 000 kg of aluminium.

Give your answer to three significant figures.

Relative atomic mass (Ar): Al = 27

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Answer = _________________ moles

(3)

(Total 16 marks)


A student investigates a potassium salt, X.

She finds that salt X:

• has a high melting point

• does not conduct electricity when it is solid

• dissolves in water and the solution does conduct electricity.

(a) What is the type of bonding in salt X?

Tick one box.

Covalent

Giant molecular

Ionic

Metallic

(1)

15

(b) What is the name given to solutions that conduct electricity?

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(1)

(c) Why does a solution of salt X in water conduct electricity?

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(1)


(d) The student electrolyses a solution of potassium chloride.

Figure 1 shows the apparatus she uses.

Figure 1

When the current is switched on, bubbles of hydrogen gas are given off at the negativeelectrode.

Explain why hydrogen is produced and not potassium.

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(2)


(e) The student then compares the relative conductivity of different concentrations ofpotassium chloride.

Figure 2 shows the apparatus she uses.

Figure 2

This is the method used.

1. Add potassium chloride solution to the water one drop at a time.

2. Stir the mixture.

3. Record the reading on the conductivity meter.


Number of dropsof potassium

chloride solution

Relativeconductivity of

solution

0 0

1 90

2 180

3 270

4 360

5 450

6 540


When there is no potassium chloride in the beaker no electrical charge flows.

Suggest why pure water does not conduct electricity.

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(2)

(f) Describe the relationship shown in the table above.

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(2)

(Total 9 marks)

The elements in Group 1 of the periodic table are metals.

(a) The elements in Group 1 are called the alkali metals.

Why are they called the alkali metals?

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(2)

16


(b) Explain the increase in reactivity of elements further down the group.

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(4)

(c) Lithium oxide is an ionic compound.

Draw a dot and cross diagram to show how lithium and oxygen combine to form lithiumoxide.

Only show the electrons in the outer shell of each atom.

Give the charges on the ions formed.

(4)

(Total 10 marks)


The salt copper sulfate can be made by reacting copper carbonate with dilute sulfuric acid.

CuCO3(s) + H2SO4(aq) CuSO4 (aq) + H2O(l) + CO2(g)

(a) Write a method that a student could use to prepare a pure, dry sample of copper

You do not need to write a risk assessment or include safety points.

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(6)

17

(b) Calculate the number of molecules in 14 g of carbon dioxide.

Give your answer in standard form.

Relative atomic masses (Ar): C = 14; O = 16

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Answer = __________________ molecules

(4)

(Total 10 marks)


This question is about magnesium.

(a) (i) The electronic structure of a magnesium atom is shown below.

Use the correct answer from the box to complete each sentence.

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 _________

(3)

18

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

Which diagram shows a magnesium ion?

Tick ( ) one box.

(1)


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

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

(i) State two observations that could be made during the reaction.

1. ____________________________________________________________

______________________________________________________________

2. ____________________________________________________________

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(2)

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

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

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

You do not need to mention safety.

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(6)

(Total 12 marks)


This question is about iron and aluminium.

(a) Iron is extracted in a blast furnace. Figure 1 is a diagram of a blast furnace.

(i) Calcium carbonate decomposes at high temperatures.

Complete the word equation for the decomposition of calcium carbonate.

calcium carbonate _____________________ +

_____________________

(2)

19

(ii) Carbon burns to produce carbon dioxide.

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

Balance the equation.

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

(1)


(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 ofiron(III) oxide.

Relative atomic masses (Ar): O = 16; Fe = 56

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Maximum mass = _______________ tonnes

(3)

(b) Aluminium is extracted by electrolysis, as shown in Figure 2.

Figure 2

(i) Why can aluminium not be extracted by heating aluminium oxide with carbon?

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(1)


(ii) Explain why aluminium forms at the negative electrode during electrolysis.

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(3)

(iii) Explain how carbon dioxide forms at the positive electrodes during electrolysis.

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(3)

(Total 13 marks)

This question is about metals.

(a) Which unreactive metal is found in the Earth as the metal itself?

Tick ( ) one box.

aluminium

gold

magnesium

(1)

20


(b) Complete the sentence.

Aluminium is an element because aluminium is made of

only one type of _________________________ .

(1)

(c) Figure 1 shows the electronic structure of an aluminium atom.

(i) Use the correct words from the box to complete the sentence.

electrons ions protons neutrons shells

The nucleus of an aluminium atom contains _______________ and

_______________ .

(2)

(ii) Complete the sentence.

In the periodic table, aluminium is in Group _______________ .

(1)


(d) Aluminium is used for kitchen foil.

Figure 2 shows a symbol on a box of kitchen foil.

The symbol means that aluminium can be recycled. It does not show the correct chemicalsymbol for aluminium.

(i) What is the correct chemical symbol for aluminium?

___________________________ .

(1)

(ii) Give two reasons why aluminium should be recycled.

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(2)

(e) Aluminium has a low density, conducts electricity and is resistant to corrosion.

Which one of these properties makes aluminium suitable to use as kitchen foil?Give a reason for your answer.

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(2)

(Total 10 marks)


This question is about electrolysis.

(a) Metal spoons can be coated with silver.This is called electroplating.

Suggest one reason why spoons are electroplated.

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(1)

21

(b) When sodium chloride solution is electrolysed the products are hydrogen and chlorine.

(i) What is made from chlorine?

Tick ( ) one box.

Bleach

Fertiliser

Soap

(1)

(ii) Sodium chloride solution contains two types of positive ions, hydrogen ions (H+) andsodium ions (Na+).

Why is hydrogen produced at the negative electrode and not sodium?

Tick ( ) one box.

Hydrogen is a gas.

Hydrogen is less reactive than sodium.

Hydrogen ions move faster than sodiumions.

(1)


(iii) Hydrogen and chlorine can be used to produce hydrogen chloride.

The diagrams in Figure 1 show how the outer electrons are arranged in an atom ofhydrogen and an atom of chlorine.

Complete Figure 2 to show how the outer electrons are arranged in a molecule ofhydrogen chloride (HCl).

(1)

(iv) What is the type of bond in a molecule of hydrogen chloride?

Tick ( ) one box.

Covalent

Ionic

Metallic

(1)


(v) Why is hydrogen chloride a gas at room temperature (20 °C)?

Tick ( ) two boxes.

Hydrogen chloride has a low boiling point.

Hydrogen chloride has a high melting point.

Hydrogen chloride is made of simple molecules.

Hydrogen chloride does not conduct electricity.

Hydrogen chloride has a giant structure.

(2)

(c) Aluminium is produced by electrolysis of a molten mixture of aluminium oxide and cryolite.This is shown in Figure 3.

(i) Name a gas produced at the positive electrode.

______________________________________________________________

(1)


(ii) Aluminium ions move to the negative electrode.

Explain why.

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(2)

(iii) At the negative electrode, the aluminium ions gain electrons to produce aluminium.

What is this type of reaction called?

Tick ( ) one box.

Combustion

Oxidation

Reduction

(1)

(iv) Aluminium has layers of atoms, as shown in Figure 4.

Complete the sentence.

Metals can be bent and shaped because the layers of atoms can ___

(1)


(d) Electrodes used in the production of aluminium are made from graphite.

(i) Which diagram, A, B or C, shows the structure of graphite?

The structure of graphite is shown in diagram

(1)

(ii) The temperature for the electrolysis is 950 °C.

Use the correct answer from the box to complete the sentence.

cross links a giant ionic lattice strong covalent bonds

The graphite does not melt at 950 °C because

graphite has _____________________________ .

(1)

(Total 14 marks)


A student investigated the temperature change when zinc reacts with copper sulfate solution.

The student used a different concentration of copper sulfate solution for each experiment.

The student used the apparatus shown below.

The student:• measured 50 cm 3 copper sulfate solution into a glass beaker• measured the temperature of the copper sulfate solution• added 2.3 g zinc• measured the highest temperature• repeated the experiment using copper sulfate solution with different concentrations.

The equation for the reaction is:

Zn(s) + CuSO4(aq) Cu(s) + ZnSO4(aq)

zinc + copper sulfate solution copper + zinc sulfate solution

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(a) The thermometer reading changes during the reaction.

Give one other change the student could see during the reaction.

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(1)

(b) Suggest one improvement the student could make to the apparatus.

Give a reason why this improves the investigation.

Improvement ________________________________________________________

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Reason ____________________________________________________________

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(2)


(c) In this question you will be assessed on using good English, organising informationclearly and using specialist terms where appropriate.

The student’s results are shown in the table.

Table

Experimentnumber

Concentration ofcopper sulfate

in moles per dm3

Increase in temperaturein °C

1 0.1 5

2 0.2 10

3 0.3 12

4 0.4 20

5 0.5 25

6 0.6 30

7 0.7 35

8 0.8 35

9 0.9 35

10 1.0 35

Describe and explain the trends shown in the student’s results.

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(6)


(Total 9 marks)

This question is about compounds.

(a) The table gives information about the solubility of some compounds.

Soluble compounds

All potassium and sodium salts

All nitrates

Chlorides, bromides and iodides, except those of silver and lead

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Use information from the table to answer these questions.

(i) Name a soluble compound that contains silver ions.

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(1)

(ii) Name a soluble compound that contains carbonate ions.

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(1)

(b) Metal oxides react with acids to make salts.

What type of compound is a metal oxide?

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(1)

(c) Lead nitrate solution is produced by reacting lead oxide with nitric acid.

(i) State how solid lead nitrate can be obtained from lead nitrate solution.

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(1)

(ii) Balance the equation for the reaction.

PbO + HNO3 Pb(NO3)2 + H2O

(1)

(iii) Give the total number of atoms in the formula Pb(NO3)2

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(1)


(d) An oxide of lead that does not have the formula PbO contains 6.21 g of lead and 0.72 g ofoxygen.

Calculate the empirical formula of this lead oxide.

Relative atomic masses (Ar): O = 16; Pb = 207

You must show your working to gain full marks.

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Empirical formula = ____________________

(4)

(Total 10 marks)

This question is about sodium chloride and iodine.

(a) Describe the structure and bonding in sodium chloride.

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(4)

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(b) When sodium chloride solution is electrolysed, one product is chlorine.

Name the two other products from the electrolysis of sodium chloride solution.

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(2)


(c) Many people do not have enough iodine in their diet.

Sodium chloride is added to many types of food. Some scientists recommend that sodiumchloride should have a compound of iodine added.

Give one ethical reason why a compound of iodine should not be added to sodium chlorideused in food.

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(1)

(d) The bonding in iodine is similar to the bonding in chlorine.

(i) Complete the diagram below to show the bonding in iodine.

Show the outer electrons only.

(2)

(ii) Explain why iodine has a low melting point.

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(3)

(iii) Explain, in terms of particles, why liquid iodine does not conduct electricity.

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(2)

(Total 14 marks)


Some pollutants cause acid rain.

A student tested 25.0 cm3 samples of three types of rainwater, P, Q and R.The student titrated the samples with sodium hydroxide solution (an alkali).

The student recorded the volume of sodium hydroxide solution needed to neutralise therainwater. The student’s results are shown in Table 1.

Table 1

Volume of sodium hydroxide needed to neutralise the rainwater in cm3

Type ofrainwater

Titration 1 Titration 2 Titration 3 Titration 4 Titration 5

P 18.0 15.5 14.5 15.0 15.0

Q 13.0 10.0 11.0 10.5 10.5

R 23.0 19.5 18.5 19.0 19.0

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(a) (i) The student calculated the mean value for rainwater R as 19.0 cm3.

Show how the student calculated the mean value for rainwater R.

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(2)

(ii) Write down P, Q and R in order of their acidity.

Most acidic _______________

_______________

Least acidic _______________

(2)


(b) A second student repeated the experiment and recorded the results in Table 2.

Table 2

Volume of sodium hydroxide

needed to neutralise therainwater in cm3

Type ofrainwater

Titration 1 Titration 2

P 17 15

Q 11 9

R 20 18

Use Table 1 and Table 2 to suggest two improvements the second student could make toobtain more accurate results.

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(2)

(c) The results of the two students show that the experiment is reproducible.

Give the reason why.

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(1)

(Total 7 marks)

Iron is extracted from iron oxide in the blast furnace.

(a) The equation for one of the reactions in the blast furnace is:

Fe2O3 + 3CO 2Fe + 3CO2

(i) Complete the word equation for this reaction.

iron oxide+

carbonmonoxide ________________ + ________________

(2)

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(ii) Oxygen is removed from iron oxide in the blast furnace.

Draw a ring around the correct answer to complete the sentence.

The iron oxide is

neutralised.

oxidised.

reduced.

(1)

(b) The diagrams represent pure iron and iron from the blast furnace.

Pure iron Iron from the blast furnace

(i) Draw one line from each statement to the correct explanation.

(2)


(ii) Explain why iron from the blast furnace is harder than pure iron.

Use the diagrams on page 4 to help you.

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(2)

(Total 7 marks)

Sulfur is a non-metal.

Sulfur burns in the air to produce sulfur dioxide, SO2

(a) Why is it important that sulfur dioxide is not released into the atmosphere?

Tick (✔) one box.

Sulfur dioxide causes acid rain.

Sulfur dioxide causes global dimming.

Sulfur dioxide causes global warming.

(1)

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(b) Sulfur dioxide dissolves in water.

What colour is universal indicator in a solution of sulfur dioxide?Give a reason for your answer.

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(2)


(c) Sulfur dioxide is a gas at room temperature.

The bonding in sulfur dioxide is covalent.

Explain, in terms of its structure and bonding, why sulfur dioxide has a low boiling point.

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(3)

(d) In this question you will be assessed on using good English, organising information clearlyand using specialist terms where appropriate.

Sulfur dioxide is produced when fossil fuels are burned.

It is important that sulfur dioxide is not released into the atmosphere.

Three of the methods used to remove sulfur dioxide from gases produced when fossil fuelsare burned are:

• wet gas desulfurisation ( W)

• dry gas desulfurisation ( D)

• seawater gas desulfurisation ( S).

Information about the three methods is given in the bar chart and in Table 1 and Table 2.

Method of removing sulfur dioxide


Table 1

Method Material used How material is obtained

W Calcium carbonate, CaCO3 Quarrying

DCalcium oxide, CaO Thermal decomposition of calcium

carbonate:

CaCO3 CaO + CO2

S Seawater From the sea

Table 2

Method What is done with waste material

WSolid waste is sold for use in buildings.Carbon dioxide is released into the atmosphere.

D Solid waste is sent to landfill.

S Liquid waste is returned to the sea.


Evaluate the three methods of removing sulfur dioxide from waste gases.

Compare the three methods and give a justified conclusion.

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(6)

(Total 12 marks)


Lead nitrate solution reacts with potassium iodide solution.

The reaction produces a solid.

Figure 1 shows the reaction occurring.

Figure 1

Lead Iodide By Der Kreole (own work) (CC-BY-3.0) via Wikimedia Commons

(a) (i) Give the name of this type of reaction.

Tick (✓) one box.

Combustion

Neutralisation

Precipitation

(1)

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(ii) Write the missing state symbols in the chemical equation.

Pb(NO3)2(aq) + 2KI(___) PbI2(___) + 2KNO3(aq)

(2)

(iii) Complete the word equation for the reaction.

lead nitrate + _________ lead iodide + _________

(2)


(iv) How is solid lead iodide separated from the solution?

Draw a ring around the correct answer.

Distillation Electrolysis Filtration

(1)

(b) A group of students investigated the movement of particles.

The students filled a container with water.

The students added a crystal of lead nitrate at position X and a crystal of potassium iodideat position Y, as shown in Figure 2.

Figure 2 – view from above

After 3 minutes solid lead iodide started to form at the position shown in Figure 3.

Figure 3 – view from above

(i) Tick (✓) the correct box to complete the sentence.

Lead ions and iodide ions move through the water by

diffusion.

evaporation.

neutralisation.

(1)


(ii) What conclusion can you make about the speed of movement of lead ions comparedwith iodide ions?

Give a reason for your answer.

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(2)

(iii) The students repeated the experiment at a higher temperature.

The solid lead iodide formed after a shorter period of time.

Explain why, in terms of particles.

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(2)

(Total 11 marks)

A student investigated the conductivity of different concentrations of sodium chloride solution.The student set the apparatus up as shown in Figure 1.

Figure 1

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The student measured the conductivity of the pure water with a conductivity meter.

The reading on the conductivity meter was zero.

(a) The student:

• added sodium chloride solution one drop at a time• stirred the solution• recorded the reading on the conductivity meter.

The student’s results are shown in the table below.

Number of drops ofsodium chloride solution

added

Relative conductivityof solution

0 0

1 100

2 120

3 310

4 400

5 510

6 590

7 710

8 800


(i) The student plotted the results on the grid shown in Figure 2.

Plot the four remaining results.

Draw a line of best fit, ignoring the anomalous result.

Figure 2

Number of drops of sodium chloride added

(3)

(ii) One of the points is anomalous.

Suggest one error that the student may have made to cause the anomalous result.

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(1)


(iii) The student wanted to compare the conductivity of sodium chloride solution with theconductivity of potassium chloride solution.

State one variable he should keep constant when measuring the conductivity of thetwo solutions.

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(1)

(b) (i) Explain, in terms of bonding, why pure water does not conduct electricity.

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(2)

(ii) Explain why sodium chloride solution conducts electricity.

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(2)

(iii) After he had added sodium chloride solution, the student noticed bubbles of gas atthe negative electrode.

Complete the sentence.

The gas produced at the negative electrode is __________________

(1)

(Total 10 marks)


Use the periodic table and the information in the table below to help you to answer the questions.

The table shows part of an early version of the periodic table.

Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7

H

Li Be B C N O F

Na Mg Al Si P S Cl

(a) Hydrogen was placed at the top of Group 1 in the early version of the periodic table.

The modern periodic table does not show hydrogen in Group 1.

(i) State one similarity between hydrogen and the elements in Group 1.

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(1)

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(ii) State one difference between hydrogen and the elements in Group 1.

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(1)

(b) Fluorine, chlorine, bromine and iodine are in Group 7, the halogens.

The reactivity of the halogens decreases down the group.

Bromine reacts with a solution of potassium iodide to produce iodine.

Br2 + 2KI 2KBr + I2

(i) In the reaction between bromine and potassium iodide, there is a reduction ofbromine to bromide ions.

In terms of electrons, what is meant by reduction?

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(1)

(ii) Complete the half equation for the oxidation of iodide ions to iodine molecules.

2I−

(2)


(iii) Explain, in terms of electronic structure, why fluorine is the most reactive element inGroup 7.

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(3)

(Total 8 marks)

A student was trying to produce hydrogen gas.

Figure 1 shows the apparatus she used.

Figure 1

(a) No gas was produced.

The student’s teacher said that this was because the substances in the flask did not react.

(i) Suggest why the substances in the flask did not react.

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(1)

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(ii) Which two substances could the student have put in the flask to produce hydrogensafely?

Tick (✓) one box.

Gold and dilute hydrochloric acid

Potassium and dilute hydrochloric acid

Zinc and dilute hydrochloric acid

(1)

(b) Another student did produce hydrogen from two substances.

Figure 2 shows the apparatus the student used to collect and measure the volume of thehydrogen gas.

Figure 2

Give the name of the apparatus labelled X.

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(1)


(c) The student did the experiment four times. Her results are shown in the table below.

Experiment Volume of hydrogen collected inone minute in cm3

1 49

2 50

3 35

4 48

(i) One of the results is anomalous.

Which result is anomalous? Write your answer in the box.

Give a reason for your choice.

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(2)

(ii) Calculate the mean volume of hydrogen collected in one minute.

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Mean volume = ____________________ cm3

(2)

(iii) Give a reason why the experiment should be repeated several times.

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(1)


(d) A teacher collected two tubes full of hydrogen gas, as shown in Figure 3.

Figure 3

She tested tube A with a lighted splint as soon as she took the bung out.

She tested tube B with a lighted splint a few seconds after taking the bung out.

(i) Suggest why tube B gave a much louder pop than tube A.

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(1)

(ii) Complete and balance the chemical equation for the reaction that takes place whenthe hydrogen reacts in this test.

H2 + O2

(2)

(Total 11 marks)


A student investigated displacement reactions of metals.

The student added different metals to copper sulfate solution and measured the temperaturechange.

The more reactive the metal is compared with copper, the bigger the temperature change.

The apparatus the student used is shown in Figure 1.

Figure 1

(a) State three variables that the student must control to make his investigation a fair test.

1. _________________________________________________________________

2. _________________________________________________________________

3. _________________________________________________________________

(3)

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(b) Figure 2 shows the thermometer in one experiment before and after the student added ametal to the copper sulfate solution.

Figure 2

Before adding metal After adding metal

Use Figure 2 to complete Table 1.

Table 1

Temperature before adding metal in °C ________

Temperature after adding metal in °C ________

Change in temperature in °C ________

(3)


(c) The student repeated the experiment three times with each metal.

Table 2 shows the mean temperature change for each metal.

Table 2

MetalMean

temperaturechange in °C

Cobalt 4.5

Gold 0.0

Magnesium 10.0

Nickel 3.0

Silver 0.0

Tin 1.5

(i) On Figure 3, draw a bar chart to show the results.

Figure 3

(3)

(ii) Why is a line graph not a suitable way of showing the results?

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(1)


(iii) Use the results to work out which metal is the most reactive.

Give a reason for your answer.

Most reactive metal _________________________

Reason _______________________________________________________

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(2)

(iv) Explain why there was no temperature change when silver metal was added to thecopper sulfate solution.

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(2)

(v) It is not possible to put all six metals in order of reactivity using these results.

Suggest how you could change the experiment to be able to put all six metals intoorder of reactivity.

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(2)

(Total 16 marks)


This question is about copper.

(a) Most of the copper extracted is used in electric circuits.

The figure below shows how impurities change the electrical conductivity of copper.

Percentage of impurities in copper

Copper extracted by smelting is about 99% pure.

The 99% pure copper produced by smelting is purified to 99.9999% pure copper byelectrolysis.

Use values from the graph to explain why copper is purified to 99.9999%.

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(2)

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

Read the information in the box.

Copper extraction

World demand for copper for the year 2011 was about 20 million tonnes.

World reserves of copper are estimated to be 700 million tonnes.

Most of the copper used is obtained from copper ores, which are mined.

The copper ore chalcopyrite is heated in a furnace to produce copper sulfide, CuS

The furnace is heated by burning fossil fuels.

Air is then blown through the hot copper sulfide, to produce copper and sulfur dioxide.

CuS + O2 → Cu + SO2

A scientist made the statement: ‘Copper should be recycled’.

Use the information in the box and your own knowledge and understanding to justify thescientist’s statement.

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Extra space _________________________________________________________

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(6)

(c) Phytomining is used to obtain copper from land that contains very low percentages ofcopper compounds.

Describe how copper compounds are obtained by phytomining.

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(3)

(Total 11 marks)


Where copper ore has been mined there are areas of land that contain very low percentages ofcopper compounds.

One way to extract the copper is to grow plants on the land.

The plants absorb copper compounds through their roots.

The plants are burned to produce copper oxide.

The copper oxide produced from plants can be reacted to produce copper or copper sulfatesolution, as shown in Figure 1.

Figure 1

(a) Draw a ring around the correct answer to complete each sentence.

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(i) Copper ores contain enough copper to make extraction of the metal

carbon neutral.

economical.

reversible.

(1)

(ii) Using plants to extract metals is called

photosynthesis.

phytomining.

polymerisation.

(1)

(iii) Copper oxide reacts with carbon to produce copper and

carbon dioxide.

oxygen.

sulfur dioxide.

(1)

(b) Copper is produced from copper sulfate solution by displacement using iron or byelectrolysis.

(i) Complete the word equation.

copper sulfate + iron ___________ + ___________

(2)


(ii) Figure 2 shows the electrolysis of copper sulfate solution.

Figure 2

Why do copper ions go to the negative electrode?

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