Answers Gateway C2

OCR GCSE Science Self-assessment quiz: Answers

C2a Foundation and Higher

Paints and pigments1 Solve the clues across. What component of paint reads down the shaded

column?

pigment [F]

1 P A I N T

2 O I L

3 G L O W

4 T H E R M O C H R O M I C

5 D Y E

6 B I N D I N G

7 S Y N T H E T I C

1 A substance used to protect surfaces such as metal or wood.

2 In one type of artist’s paint, the pigment is dissolved in oil .

3 Phosphorescent pigments glow in the dark.

4 A pigment which changes colour when heated.

5 A substance used to colour fabrics.

6 A binding medium contains molecules which join together when

the paint sets.

7 This type of dye is made in the laboratory.

2 True or false? Put T or F in the boxes. [F]

Emulsion paints are water based paints. T

Paints are solutions of pigments in solvents. F

As paint dries, the solvent reacts with the binding medium. F

All paints have the same solvent. T

3 Fill in the blank spaces using the words: colours fade increased synthetic [F/H]

Synthetic dyes do not fade easily and have increased

the number of colours available.

4 Link these sentences by putting A, B, C or D in the boxes on the right. [F/H]

…The components of a colloid will not separate because A … the solvent evaporates. D

…Oil paints dry when B … the particles change their arrangement. C

…Thermochromic paints change colour when C … the oil is oxidised by the air. B

…Paints dry because D … the particles are dispersed throughout the mixture. A

5 Tick the correct statements about phosphorescent pigments. [H]

They have no uses.

They emit light even if they have been kept in the dark for a long time.

The greater the light intensity on the pigment, the longer they glow for.

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C2a Foundation and Higher

They are safer than radioactive pigments.

Construction materials1 Solve the clues across. The answer down the shaded column is the name of

metamorphic rock. What is this rock? marble [F]

1 M I N I N G2 Q U A R R Y

3 G R A N I T E4 C A R B O N A T E

5 G L A S S

6 C E M E N T

1 A way of getting minerals from the ground

2 An open pit for the extraction of rocks

3 A very hard, crystalline rock

4 Limestone is calcium carbonate .

5 Transparent material made by heating sand and limestone to a high temperature

6 Substance made when limestone and clay are heated together

2 True or false? Put T or F in the boxes. [F/H]

Calcium carbonate decomposes to make calcium oxide and water. F

During thermal decomposition a substance is chemically changed into two or more new substances.

T

Limestone decomposes rapidly at room temperature. F

Marble cannot undergo thermal decomposition. F

3 Link these sentences by putting A, B, C or D in the boxes on the right. [H]

Limestone is a … [A] … formed by the action of high temperature and pressure on other calcium carbonate rocks.

C

Marble is … [B] … a rock from which a metal can be extracted. A

Granite is … [C] … a sedimentary rock. D

An ore is … [D] … an igneous rock. B

4 Complete these sentences using the words: composite reinforced stronger support.[H]

Reinforced concrete is a composite material containing concrete and

a steel support . The steel makes the concrete stronger .

5 Complete the symbol equation for the decomposition of calcium carbonate. [H]

CaCO → Ca O + CO3 2




C2c Foundation and Higher

Does the Earth move?1 Solve the clues across. The answer down the shaded column is the name of the element

that is present in the Earth’s core. Name this element. Iron [F]

1 L I T H O S P H E R E2 R A T E

3 V O L C A N I C

4 M A N T L E

1 The rigid outer part of the Earth

2 The size of the crystals in an igneous rock is related to the rate of cooling

3 Volcanic soil is very fertile

4 The zone between the Earth’s crust and core

2 Unscramble the letters to find the names of: [F]

a rock with large crystals TEARING GRANITE

a silica rich igneous rock with small crystals HOLY RITE RHYOLITE

an iron rich rock with small crystals AT SLAB BASALT

3 Complete these sentences about rocks using the following words: [F/H]

dense large mantle rapidly slowly small tectonic

Tectonic plates float on top of the mantle because they are less

dense than the mantle. Magma from the mantle that cools slowly

forms rocks with large crystals. Magma that cools rapidly

produces rocks with small crystals.

4 True or false? Put T or F in the boxes. [H]

Geologists are able to predict when earthquakes are going to happen with 100% certainty.

F

Volcanoes which produce runny basalt are likely to erupt non-explosively. T

Volcanoes are most frequently found in the centre of a continental plate. F

Pumice is a rock formed by the explosive action of volcanoes. T

5 Match the letters in the diagram to the following: [H]

continental plate D

magma chamber B

oceanic plate A

subducting plate C



B

D

CA


C2c Foundation and Higher

Metals and alloys1 Unscramble the letters to find the names of some metals and alloys. [F]

PC ROPE DALE CURRY ME DS ROLE I NO LINTCOPPER LEAD MERCURY SOLDER NITINOL

2 Tick the boxes to show which of the following are alloys [F]

bronze copper

iron brass

zinc steel

lead amalgam

3 Complete these sentences about the extraction of copper using words from the list. [F]

carbon electrolysis heating ore purified

Copper is extracted by heating malachite ore with carbon .

The copper is then purified using electrolysis .

4 True or false? Put T or F in the boxes. [F/H]

Solder is a mixture of tin and lead. T

The melting point of an alloy is the average of the melting points of the elements form which it is made.

F

Amalgam is used for filling teeth. T


Some smart alloys have shape memory properties. T

Brass is a compound of copper and zinc. F

Smart alloys have the same properties at all temperatures. F

Smart alloys can remember the shape that they were manufactured at. T

6 Complete these sentences about the electrolysis of copper using words from the list. [H]

electrolyte impure negative positive pure sulfate

Copper is electrolysed using impure copper as the anode ( positive

electrode) and pure copper as the cathode ( negative electrode). The

electrolyte is a solution of copper(II) sulfate .




C2e Foundation and Higher

Cars for scrap1 Solve the clues across. What metal used in car making reads down the shaded column?

steel [F]

1 R U S T

2 P L A S T I C

3 C O P P E R

4 C O R R O D E5 R E C Y C L I N G

1 A substance formed when iron corrodes in the air in the presence of moisture

2 A substance often used for car bumpers

3 A pinkish-brown metal which is an excellent electrical conductor

4 A word meaning ‘eating away’ at the surface (especially applied to metals)

5 One way of conserving natural resources

2 True or false? Put T or F in the boxes. [F]

Iron is less dense than aluminium. F

Both aluminium and iron are magnetic. F

Iron corrodes easily in moist air, aluminium does not. T

Both iron and aluminium are malleable. T

3 Which of the following are advantages and which are disadvantages of recycling metals. Put A

or D in the boxes. [F/H]

Disposal problem are reduced. A

Many metals are alloys. D

Less energy is used than extracting metals from their ores. A

Wires often have a plastic coating. D

4 Tick the correct statements about the use of aluminium in cars. [H]

A car made of aluminium will be lighter than one made from steel.

It is cheaper to make a car from aluminium than from steel.

You will get a better fuel economy from a car made of aluminium than one made of iron.

A car made from aluminium will corrode at the same rate as one made from iron.

5 Complete the word equation for the rusting of iron. [H]

iron + oxygen + water → hydrated iron(III) oxide




C2f Foundation and Higher

Clean air1 Solve the clues across. Sulfur dioxide and nitrogen dioxide in the air chemically

erode buildings. The blank space gives the word in the shaded column down. [F]

1 N I T R O G E N

2 C O N V E R T E R

3 P O I S O N O U S4 O X I D E S

5 W A T E R

1 The gas which makes up four fifths of the air

2 A catalytic converter removes carbon monoxide and nitrogen oxides from the

exhaust gases from a car engine

3 Carbon monoxide is a poisonous gas

4 Oxides of nitrogen are formed in the internal combustion engine

5 Water vapour is found in clean air

2 What are the percentages of carbon dioxide, nitrogen and oxygen in the air? Put the correct

letters from the list in the relevant boxes. [F]

0% 0.035% 1% 21% 48% 78% 90% 99%A B C D E F G H

carbon dioxide B nitrogen F oxygen D

3 Complete the following sentences using words from the list. [F/H]

acid aquatic burnt coal corrodes dissolves fossil sulfur

Fossil fuels such as coal and oil have small amounts of sulfur

in them. When these fuels are burnt , sulfur dioxide is formed which reacts

in rainwater to form acid rain. Acid rain kills aquatic life and corrodes metals.


The early atmosphere of the Earth was formed by volcanic activity. T

The Earth’s atmosphere has been the same for the last 4 000 million years. F

Photosynthesis produced most of the oxygen in the present day atmosphere. T

The balance between photosynthesis and respiration keeps the composition of atmosphere approximately constant.

T

5 Balance this equation for one of the reactions taking place in a catalytic converter. [H]

2 CO + 2NO → N + 2CO




C2f Foundation and Higher

2 2

Faster or slower? (1)1 Arrange the reactions A, B, C and D according to their rate. Put the fastest first. [F]

A iron nail rusting in damp air B limestone weathering away

C TNT blowing up a chimney stack D wooden spill burning

fastest → C D A B ← slowest

2 Solve the clues across. The shaded column tells us how fast the reaction goes (the rate). [F]

1 G R A P H2 A C I D

3 C A R B O N A T E

4 C O L L I D E

1 A graph of volume of gas released during a reaction against time shows how

fast a reaction is proceeding

2 Hydrogen is given off when magnesium reacts with this

3 Carbon dioxide is released when calcium carbonate reacts with hydrochloric acid

4 A chemical reaction takes place when particles collide .

3 True or false. Put T or F in the boxes [F/H]

As the temperature of a reaction mixture increases the particles get more crowded together.

F

Decreasing the concentration of acid decreases its rate of reaction with magnesium because the particles get further apart.

T

Increasing the temperature increases the energy of the particles. T

Decreasing the pressure increases the rate of reaction. F

4 Tick the correct statements. [H]

Increasing the temperature decreases the average energy of particles of hydrochloric acid.

Increasing the temperature by 20°C speeds up a reaction about four times.

Increasing the temperature increases the time taken for the reaction to finish.

Increase in temperature results in more energetic collisions.

5 What is the initial rate of reaction in the graph on the right? Tick one box. [H]

0.5 cm3/s 2.0 cm3/s 4.0 cm3/s

At what time is the reaction complete?

60 s



0 20 40 6080

Time/s

80

60

40

20

Vol

ume/

cm3

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