Collins KS3 Science Now Assessment Pack - sample proof

SCIENCE NOW KS3

ASSESSMENT PACK

AIDAN GILL AND SAM HOLYMAN

1 Some chemicals have hazard warning signs.

a What does mean?

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Choose one correct answer.

b Suggest one safety precaution when using an acid which is labelled as an irritant. Choose one correct answer.

Wear a hair covering

Wear an apron or lab coat

Wear eye protection

Use rubber washing up gloves

c Which is the pH of an acid?

2 This question is about chemical reactions.

a Match the name of the chemical reaction to its description. [3 marks]

Name of chemical reaction

Displacement

Thermal decomposition

Combustion

Neutralisation

Description

Using heat energy to break down a substance.

Burning of a fuel with oxygen from the air.

A reaction between an acid and a base to make a salt.

When a more reactive metal takes the place of a less reactive metal from its compound.

b Give one observation which suggests a chemical change has happened. [1 mark]

3 Indicators can be used to classify a substance as acid or alkali.

Maximum 4 marks

a Explain how litmus can be used to classify a liquid as an acid or an alkali. [4 marks]

b An acidic solution is tested with universal indicator. What colour would the universal indicator turn? [1 mark]

4 Steve wanted to investigate the thermal decomposition of copper carbonate.

Maximum 5 marks

Steve used the equipment below.

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a Complete the word equation for the thermal decomposition of copper carbonate. [2 marks]

Copper carbonate  _________________________ + _________________________

b Classify this reaction as exothermic or endothermic. Explain your answer. [2 marks]

Classification:

Reason:

c Explain why copper oxide and copper carbonate are bases but not alkalis.

[2 marks]

Maximum 6 marks

5 Jemma wanted to investigate the combustion of candle wax. She lit the candle and drew the gases that were made through a piece of equipment to test them.

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a Name the two reactants in Jemma’s investigation. [2 marks]

b The limewater went from colourless to cloudy.

This proves that a gas was made. Name the gas [1 mark]

c Jemma noticed that the funnel turned black.

Name the substance that made the funnel go black. [1 mark]

d Explain how a combustion reaction can also be classified as an oxidation reaction. [1 mark]

Maximum 5 marks

6 Li wanted to investigate displacement reactions between copper sulfate solution and different metals.

They measured the same volume of copper sulfate each time and put the same mass of the metal into the beaker.

They measured the start and end temperature.

Zinc 16 18 4 17

Magnesium 38 37 37 Y

a What is the independent variable? [1 mark]

b What measuring instrument would Li use to monitor the dependent variable? [1 mark]

c Circle the anomalous result in the table. [1 mark]

d Calculate the missing mean Y.

Give your answer to one decimal place. [3 mark]

e Write the order of the metals from most to least reactive. [1 mark]

Maximum 7 marks

Assessment 10

Answers

Question Answer

1a corrosive

1b Wear eye protection

1c 1

2a

2b Any one of the following:

• bubbles of gas/fizzing/effervesce

• a change in temperature

• a colour change

[1] for one line [2] for two or three correct lines [3] for all correct lines 3 AO1

• a change in mass Accept a solid/precipitate being made

3a Indicative content:

Add a few drops of litmus solution to the sample or dip litmus paper into the sample

Look at the colour

If litmus is red then the solution is an acid

If the litmus is blue then the solution is an alkali

This question is a levelled response.

0 marks – no relevant content

1-2 marks –some relevant points are made but not necessarily given in a logical order.

3-4 marks – a logical flow of information forms a through explanation including expected results. 4 AO1

3b Accept any of the following: 1 AO2

Red, orange, yellow

4a copper oxide carbon dioxide Accept in any order 1 1 AO2

4b Endothermic Energy taken in by the reaction 1 1 AO3

4c Reacts with acid so is a base Doesn’t dissolve in water/insoluble in water so can’t be an alkali 1 1 AO3

5a Wax

5b Carbon dioxide

5c Carbon

5d The atoms in the fuel have oxygen added to them Accept oxygen is added 1 AO2

6a metal 1 AO2

6b thermometer 1 AO2

6c Circle zinc run three (4) 1 AO3

6d 38 + 37 + 37 = 112 112 / 3 = 37.333 Y = 37.3oC Give three marks for the correct answer without working 3 AO2

6e Magnesium, zinc, nickel Must be in this order.

Accept: Mg, Zn, Ni 1 AO3