Candidate Name Centre Number Candidate Number 0

Candidate Name Centre Number Candidate Number 0

GCSE SCIENCE A

HIGHER TIER (Grades D-A*)

CHEMISTRY 1 – The Earth and its resources SPECIMEN PAPER

(1 hour)

INSTRUCTIONS TO CANDIDATES

Write your name, centre number and candidate number in the spaces at the top of this page.

Answer all questions.

Write your answers in the spaces provided in this booklet.

INFORMATION FOR CANDIDATES

The number of marks is given in brackets at the end of each question or part-question.

You are reminded that assessment will take into account the quality of written

communication used in your answer to questions 3 and 9(c).

Answer all questions.

1. (a) The table below shows some physical properties of Group 1 elements.

Element Melting point / °C

Boiling point / °C

Density / gcm ^-3

Electrical conductivity lithium 180 1340 0.50 good

sodium 880 0.97 good

potassium 63 766 0.86 good

rubidium 39 686 1.50 good

caesium 29 669 1.90 good

Use only the information in the table to answer parts (i) and (ii).

(i) State one property of Group 1 metals which is common to all metals. [1]

...

(ii) Predict the approximate value for the melting point of sodium and give

a reason for your choice. [2]

Melting point ... °C

Reason ...

...

(b) Sodium reacts vigorously with fluorine to give sodium fluoride as shown in the following word equation.

sodium + fluorine sodium fluoride

Balance the symbol equation shown below. [2]

Na + F ₂ NaF

(c) Sodium fluoride is added to the water supply in some areas because fluoride ions have been shown to cause a reduction in tooth decay.

Scientists established this link by carrying out large scale surveys.

(i) Give a reason why scientists required large numbers of people to complete their surveys in order to establish the link between fluoride

ions and a reduction in tooth decay. [1]

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(ii) Suggest why it would be better for this type of survey to be carried out by an independent consumer group rather than by a company which

manufactures toothpaste. [1]

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(iii) Give one reason why many people are against the fluoridation of the

water supply. [1]

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2. John and Betsan wanted to investigate the link between the number of carbon atoms present in molecules of different fuels and the amount of heat they released on burning.

They were told that molecules of fuels A-E had the following numbers of carbon atoms.

Fuel Number of carbon atoms per molecule

A 1 B 2 C 3 D 4 E 5 They decided to use the apparatus below to make their measurements.

They recorded the initial temperature of the water and lit the burner. They placed the

burner below the flask and heated the water for 1 minute. They then removed the

burner and noted the highest temperature recorded on the thermometer.

(i) In addition to the heating time, name one of the variables that they should keep constant during each of their experiments in order to ensure that their

results are valid. [1]

...

They collected the following results for fuels A-D but did not have a sample of fuel E to test.

Temperature of water (°C) Fuel Number of carbon atoms per

molecule

Initial Final Increase

A 1 19 29 10

B 2 20 32 12

C 3 20 35 15

D 4 19 38

E 5

(ii) Calculate, and record in the table, the increase in temperature for fuel D. [1]

(iii) Plot a graph to show the relationship between the number of carbon atoms per molecule and the temperature increase when each fuel is burned for

1 minute. [3]

Temperature increase

/ ºC

0 1 2 3 4 5

Number of carbon atoms

(iv) Describe the general trend shown by your graph. [1]

...

(v) Use your graph to predict the temperature increase which would be produced

by burning fuel E for 1 minute. [1]

...°C

(vi) Betsan told John that they should try to find out whether or not the results are 'repeatable'. Describe how they should do so. [1]

...

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(vii) State what you think is the most likely reason that the values they measured are not the true values. Suggest how the method used could be changed in

order to improve the quality of the results. [2]

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3. It has been suggested that waste plastics could be recycled and used to manufacture houses cheaply and quickly.

Evaluate this potential use of waste plastics. [6 QWC]

In your answer you should refer to

• the properties of plastics

• what happens to most plastics once they have been used

• the need to make the best possible use of the Earth's natural resources

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4. The following graph shows how levels of carbon dioxide in the air have changed between 1750 and the year 2000.

(i) Compare the pattern of change shown in the graph before and after 1900. [2]

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(ii) Give one possible reason for the change seen after 1900. [1]

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(iii) I Describe what effect these changes in levels of carbon dioxide are believed to be having on the temperature of the Earth's atmosphere.

[1]

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II What is the name given to this effect? [1]

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III Give one possible result of this change in the temperature of the

Earth's atmosphere. [1]

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5. (a) The diagram below shows some reactions of dilute hydrochloric acid.

Give the name for

(i) metal A, ... [1]

(ii) gas B, ... [1]

(iii) colourless solution C, ... [1]

(iv) black powder D. ... [1]

(b) (i) Describe how you could prepare crystals of copper(II) chloride from copper(II) carbonate and hydrochloric acid. [3]

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...

...

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(ii) Write the formula for copper(II) chloride. [1]

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dilute hydrochloric acid zinc chloride solution

and gas B

copper(II) chloride solution

copper(II) chloride solution and carbon

dioxide gas

colourless solution C metal A

copper(II) carbonate black

powder D

sodium hydroxide

solution

6. (a) The following diagram shows how aluminium is extracted from its ore by electrolysis.

(i) Give the name of the electrolyte used in this extraction. [1]

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(ii) The word equation for the overall reaction that takes place during the extraction is shown below.

During the reaction, reduction takes place. State the meaning of the

term reduction. [1]

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(iii) The extraction of aluminium from its ore uses large amounts of electricity and is therefore very expensive. State one method of

reducing the cost of aluminium metal. [1]

...

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(iv) Aluminium is a very good conductor of electricity and has a low density.

Give one use of aluminium which relies on both of these properties.

[1]

...

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aluminium oxide aluminium + oxygen

(b) (i)

Copper coins once contained 97% copper and 1 tonne of 1p and 2p pieces would amount to about £3000 in total.

Use the graph above to suggest a reason why ‘coppers’ are now made of steel with a thin copper coating. [1]

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(ii) Suggest one reason for the increasing demand for copper in the

‘electronic age’. [1]

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7. (a) Crude oil can be separated into fractions using fractional distillation. The following table shows some properties of the first three fractions collected.

Fraction Boiling point range

Size of molecules (No. C atoms)

Colour of

fraction Ease of burning

A Up to 80 ºC 1-6 colourless lights easily and burns with a clean flame

B 80-150 ºC 6-11 yellow more difficult to light and produces some smoke

C over 150 ºC 11 and above dark orange

difficult to ignite and gives smoky flame

(i) State the relationship between the number of carbon atoms present in the molecules of each fraction and its boiling point range. [1]

...

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(ii) Sate which fraction, A, B or C, would be most useful as a fuel, giving a

reason for your answer. [1]

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(b) Fractions not suitable for use as fuels can be cracked. State the conditions required for cracking to occur and briefly describe why this is an important

reaction. [2]

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8. Metal X is suspected to lie between magnesium and iron in the reactivity series.

Describe, and explain, how you would show this was true using the following chemicals:

magnesium ribbon, iron filings and metal X

solutions of magnesium nitrate, iron nitrate and the nitrate of metal X. [4]

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9. Hydrogen gas is potentially the answer to any future world fuel shortage.

Hydrogen is the most abundant element in the universe and is in plentiful supply on Earth – combined with oxygen in water molecules.

Electrolysis can be used to split water molecules to produce hydrogen gas, H ₂ , and oxygen gas, O ₂ .

(a) State why electrolysis of water produces twice the amount of hydrogen as it

does oxygen. [1]

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(b) Describe how you would prove that a gas is indeed hydrogen. [1]

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(c) Use the following data to evaluate the potential of hydrogen as a replacement for petrol and diesel to fuel cars. A complete response will include reference

to advantages and disadvantages. [6 QWC]

Source water Extraction method requires electricity

Amount of energy released on burning large

Product of burning water vapour

Ease of ignition ignites easily

State at room temperature and pressure gas

Stability forms explosive mixture with air

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FORMULAE FOR SOME COMMON IONS

POSITIVE IONS NEGATIVE IONS

NAME FORMULA NAME FORMULA

Aluminium Al ³⁺ Bromide Br ^-

Ammonium NH 4 + Carbonate CO 3 2-

Barium Ba ²⁺ Chloride CI ^-

Calcium Ca ²⁺ Fluoride F ^-

Copper(II) Cu ²⁺ Hydroxide OH ^-

Hydrogen H ⁺ Iodide I ^-

Iron(II) Fe ²⁺ Nitrate NO ₃ ^-

Iron(III) Fe ³⁺ Oxide O ^2-

Lithium Li ⁺ Sulfate SO ₄ ^2-

Magnesium Mg ²⁺

Nickel Ni ²⁺

Potassium K ⁺

Silver Ag ⁺

Sodium Na ⁺