oxford cambridge and rsa gcse (9–1) chemistry a ... use black ink. you may use an hb pencil...

INSTRUCTIONS• Use black ink. You may use an HB pencil for graphs and diagrams.• Complete the boxes above with your name, centre number and candidate number.• Answer all the questions. • Write your answer to each question in the space provided. Additional paper may be

used if required but you must clearly show your candidate number, centre number and question number(s).

• Do not write in the barcodes.

INFORMATION• The total mark for this paper is 90.• The marks for each question are shown in brackets [ ].• Quality of extended response will be assessed in questions marked with an asterisk (*).• This document consists of 28 pages.

Turn over© OCR 2017 Practice paperDC (KS/SW) 164463/3

Last name

First name

Candidatenumber

Centrenumber

Oxford Cambridge and RSA

GCSE (9–1) Chemistry A (Gateway Science)J248/03 Paper 3, C1–C3 and C7 (Higher Tier)

Year 11 TestTime allowed: 1 hour 45 minutes

You must have:• a ruler (cm/mm)• the Data Sheet for GCSE Chemistry A

You may use:• a scientific calculator• an HB pencil

H

OCR is an exempt Charity

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J248/03© OCR 2017 Practice paper

SECTION A

You should spend a maximum of 30 minutes on this section.

Answer all the questions.

1 A student uses chromatography to separate a mixture of coloured dyes.

X

What is the name of the dotted line marked X?

A Chromatogram

B Rf line

C Solvent

D Solvent front

Your answer [1]

3

J248/03 Turn over© OCR 2017 Practice paper

2 A compound is formed from 2 ions, Fe2+ and SO42–.

What is the formula of the compound?

A FeSO4

B Fe2(SO4)2

C Fe2(SO4)3

D Fe3(SO4)2

Your answer [1]

3 Diamond is a form of carbon.

Conducts electricity Type of structure

A No Giant covalent

B No Giant ionic

C Yes Giant covalent

D Yes Giant ionic

Which row of the table describes diamond?

Your answer [1]

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4 Mendeleev developed an early version of the Periodic Table. Mendeleev’s Periodic Table is different to the modern Periodic Table.

Mendeleev’s Periodic Table Modern Periodic Table

A contains gaps elements arranged by atomic mass

B elements arranged by atomic mass contains gaps

C elements arranged by atomic mass elements arranged by atomic number

D elements arranged by atomic number elements arranged by atomic mass

Which row of the table describes both Periodic Tables?

Your answer [1]

5 Hydrogen is a gas at room temperature (20 °C).

HH

H

H

H

H

HH

Bonds between hydrogen atoms in a hydrogen molecule Bonds between hydrogen molecules

A strong strong

B strong weak

C weak strong

D weak weak

Which row of the table explains why?

Your answer [1]

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6 A student does an electrolysis experiment of a molten liquid using inert electrodes.

The table shows the substances produced at each electrode.

Substance produced at anode Substance produced at cathode

A Metal Metal

B Metal Non-metal

C Non-metal Metal

D Non-metal Non-metal

Which row of the table is correct?

Your answer [1]

7 A metre ruler is a piece of wood which is 1 m long.

The metre ruler is larger than the atom.

How many times larger is the metre ruler?

A 10–14

B 10–10

C 1010

D 1014

Your answer [1]

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8 An atom of scandium can be written as:

Sc4521

What information does 45–21 tell you?

A The number of neutrons in a scandium is 24.

B The number of protons and electrons in a scandium is 24.

C The number of protons and neutrons in a scandium is 24.

D The number of protons in a scandium is 24.

Your answer [1]

9 What is meant by a pure sample in chemistry?

A A raw material.

B A sample containing foods.

C A sample containing only one chemical.

D A sample with only water added.

Your answer [1]

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10 The reaction profile of a chemical reaction is shown below.

P

Progress of the reaction

Energy

S

P S

A Activation energy Energy change

B Energy change Activation energy

C Products Reactants

D Reactants Products

What is the correct name for P and S?

Your answer [1]

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11 The total mass of the reactants and products in a chemical reaction changes with time.

Which graph shows how?

0

Mass

TimeA

0

Mass

TimeB

0

Mass

TimeC

0

Mass

TimeD

Your answer [1]

12 Atoms contain protons, neutrons and electrons.

Which row of the table shows the correct ratios?

Proton charge : Electron charge Proton mass : Electron mass

A 1 : –1 1 : 1

B 1 : –1 1800 : 1

C 1 : 1 1 : 1

D 1 : 1 1 : 1800

Your answer [1]

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13 The pH of a solution of hydrochloric acid is changed from 3 to 1.

What happens to the concentration of hydrogen ions in the solution?

A Decreases by a factor of 2.

B Decreases by a factor of 100.

C Increases by a factor of 2.

D Increases by a factor of 100.

Your answer [1]

14 What is a mole?

A The amount of atoms in 12.0 g of carbon-12.

B The amount of substance with the same number of atoms as 1.0 g of carbon-12.

C The amount of substance with the same number of atoms as 12.0 g of carbon-12.

D The number of atoms in 1.0 g of carbon-12.

Your answer [1]

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15 A student uses a spirit burner to increase the temperature of a beaker of water.

Beaker

Spirit burner

Thermometer

100 g Water

Liquid fuel

The temperature of the water increases by 15 °C. The mass of fuel burned is 1 g. Use the formula: energy transferred = mass × 4.2 × temperature change

Calculate the energy transferred to the water when the fuel burns.

A 63 J

B 6237 J

C 6300 J

D 6 300 000 J

Your answer [1]

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SECTION B

Answer all the questions.

16 Calcium sulfide (CaS) is an ionic compound.

Sulfur atomCalcium atom

Describe why calcium sulfide is an ionic compound.

Use the diagram to help explain your answer.

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17 Many scientists are researching the applications of nanoparticles.

(a) Suggest one use of nanoparticles.

.............................................................................................................................................. [1]

(b) Below are two scientists’ views on nanoparticles.

Scientist A(Research scientist)

Scientist B(Director of a nanotechnology company)

• I found that some nanoparticles can damage DNA in cells

• We need to do more research on using nanoparticles

• We must be careful - nanoparticles must not be released into the atmosphere.

• There are lots of nanoparticles, many have medical uses

• We have been exposed to nanoparticles for many years

• There is no evidence nanoparticles are dangerous.

(i) Evaluate the reliability of each scientist’s statement.

Scientist A .........................................................................................................................

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Scientist B .........................................................................................................................

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(ii) Use the statements to explain why scientists still use nanoparticles.

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(c) When scientists carry out research, they publish their results.

(i) Why is it important to publish their results?

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...................................................................................................................................... [1]

(ii) Publishing results allows other scientists to peer review the research.

Explain why this is important.

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

...................................................................................................................................... [1]

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18 Organic chemistry is the chemistry of carbon compounds.

(a) Carbon can form many different organic compounds.

State two types of structure that carbon can make.

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

2 ........................................................................................................................................... [1]

(b) Propanone is an organic compound.

This is a data sheet giving information about propanone.

Compound: propanone

Alternative name acetone

Formula C3H6O

Relative molecular mass 58

Boiling point 56 °C

Melting point –95 °C

Solubility Mixes with hot and cold water

Uses Nail varnish remover

A student accidentally mixes some propanone and water.

What method can she use to separate the propanone and water?

Explain how the method works.

Separating method ...................................................................................................................

Explanation ...............................................................................................................................

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.............................................................................................................................................. [3]

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19 Hydrochloric acid reacts with calcium carbonate to make carbon dioxide.

(a) At the start of the reaction the pH of the hydrochloric acid is 1.

What happens to the pH of the reaction mixture during the reaction? Explain your answer.

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

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

.............................................................................................................................................. [2]

(b) Look at the symbol equation for the reaction.

HCl(…..…..) + CaCO3(……....) CaCl2(aq) + CO2(……...) + H2O(……....)

(i) Complete the equation by adding the correct state symbols.

One is already completed for you. [2]

(ii) The equation is not balanced.

Write the balanced symbol equation for the reaction.

...................................................................................................................................... [1]

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20 This question is about elements and the Periodic Table.

(a) Elements D and E are found in the same group.

What conclusion can you make about the electronic structures of D and E?

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

.............................................................................................................................................. [1]

(b) Elements H and J are found in the same period.

What conclusion can you make about the electronic structures of H and J?

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

.............................................................................................................................................. [1]

(c) The diagrams show the electronic structures of two elements, Q and M.

Q M

Which element is a metal? Explain your answer.

Element ....................................................................................................................................

Explanation ...............................................................................................................................

.............................................................................................................................................. [1]

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21* A chemistry student prepares a sample of potassium sulfate using a neutralisation reaction.

Here are some chemicals the student has in the laboratory.

Chemical Formula

Nitric acid HNO3

Potassium K

Potassium hydroxide KOH

Sulfuric acid H2SO4

Water H2O

By choosing chemicals from the table, describe and explain the reaction the student uses and the ions involved.

You should include balanced symbol equations in your answer.

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22 (a) Explain the difference between a dilute acid and a weak acid.

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

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

.............................................................................................................................................. [2]

(b) Complete the equation for the reaction of magnesium with an acid.

acid + magnesium ....................................................................................................... [2]

(c) A student does an experiment with two acids, A and B. She wants to find out which acid is stronger.

20

Acid

Gas syringe

Magnesium ribbon

60 100 cm340 80

• She adds acid A to a conical flask.

• She places some magnesium ribbon in acid A.

• She measures the volume of gas given off using a gas syringe.

• She repeats the experiment with acid B.

Suggest two ways to improve this method.

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

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

2 ................................................................................................................................................

.............................................................................................................................................. [2]

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(d) Look at the results of the student’s experiment.

Time (s) Volume of gas using acid A (cm3)

Volume of gas using acid B (cm3)

0 0 0

10 46 25

20 56 43

30 57 52

40 58 55

50 58 55

60 58 55

(i) Describe how the volume of gas changes with time for acid B.

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

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

...................................................................................................................................... [2]

(ii) Which acid, A or B, is stronger?

Use the results to help explain your answer.

Stronger acid .....................................................................................................................

Explanation .......................................................................................................................

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...................................................................................................................................... [3]

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23 When copper powder is heated in air, copper oxide is produced.

Heat

Copper powder

Tongs toraise lidCrucible

The experiment is repeated twice.

(a) Look at the results from experiment 1.

Copper Oxygen

Mass (g) 1.76 0.44

Calculate the number of moles of copper in this sample of copper oxide.

Show your working clearly.

Answer = .................................mol [3]

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(b) (i) Explain what the term empirical formula means.

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

...................................................................................................................................... [1]

(ii) Look at the results from experiment 2.

Copper Oxygen

Number of moles (mol) 0.048 0.024

Copper oxide contains the ions Cu2+ and O2–.

Explain why the results are incorrect.

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...................................................................................................................................... [3]

(c) The student measures the mass of copper, oxygen and copper oxide accurately.

Write down other practical steps the student can do to obtain an accurate formula.

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.............................................................................................................................................. [2]

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24 A teacher sets up an electrolysis experiment.

(a) Describe how the teacher electrolyses a molten liquid.

You may include a labelled diagram in your answer.

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(b) The teacher electrolyses molten lead bromide, PbBr2.

(i) Write down ionic equations to show what happens at each electrode.

At the anode ......................................................................................................................

At the cathode .............................................................................................................. [3]

(ii) What is meant by oxidation?

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

...................................................................................................................................... [1]

(iii) At which electrode does reduction occur?

...................................................................................................................................... [1]

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25 (a) Zinc carbonate reacts with nitric acid to produce carbon dioxide.

ZnCO3 + 2HNO3 Zn(NO3)2 + CO2 + H2O

Calculate the mass of carbon dioxide produced from 0.66 g of zinc carbonate. Give your answer to 2 decimal places.

Answer = .................................... g [4]

(b) Water has a relative formula mass of 18.

Calculate the number of molecules in 8 g of water. Give your answer to 2 significant figures.

Avogadro’s constant = 6.023 × 1023 molecules / mol.

Answer = .................................mol [3]

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26 (a) Propanone burns in oxygen to form carbon dioxide and water.

H

H

CH +HC O4 O

H

H

C

O O3

3

+

C O

OH H

The table shows some bond energies.

Bond Bond energy (kJ / mol)

C=O 803

C–C 356

C–H 416

O=O 498

O–H 467

Use the information to calculate the energy change for this reaction.

Answer = ........................... kJ / mol [4]

(b) How can you tell if a reaction is exothermic?

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

.............................................................................................................................................. [1]

25


BLANK PAGE

PLEASE DO NOT WRITE ON THIS PAGE

Turn over for next question

26


27 A teacher uses models to explain evaporation and dissolving.

(a) The teacher evaporates water using a Bunsen burner.

He uses glass marbles to represent particles of water. Describe two disadvantages of this model.

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

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

2 ................................................................................................................................................

.............................................................................................................................................. [2]

(b) The teacher dissolves a tablet in warm water.

He uses a block of wood to model the whole tablet.

He uses 10 small cubes to model a crushed tablet.

2 cm

5 cm

1 cm 1 cm

1 cm

Small cubes(crushed tablet)

Block of wood(whole tablet)

(i) Show that the surface area to volume ratio for the block of wood (whole tablet) is 3.4 : 1.

Use the measurements in the diagram to help you.

Answer = ....................................... [4]

27


(ii) A pupil measures the time taken to dissolve a tablet in 50 cm3 of water.

He crushes a tablet into 10 pieces and dissolves it in water.

He repeats the experiment with a whole tablet.

Look at the results of his experiment.

Time for tablet to dissolve(s)

Surface area to volume ratio

Crushed tablet 37 6 : 1

Whole tablet 67 3.4 : 1

Evaluate the effectiveness of crushing the tablet into 10 pieces.

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END OF QUESTION PAPER

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Oxford Cambridge and RSA

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oxford cambridge and rsa gcse (9–1) chemistry a ... use black ink. you may use an hb pencil...

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