IGCSE Coordinated Chemistry Workout 30

Which statement about fractional distillation is correct?

• A chemical change occurs because new substances are formed.

• A chemical change occurs because no new substances are formed.

• A physical change occurs because new substances are formed.

• A physical change occurs because no new substances are formed.

Hand warmers keep hands warm on a cold day.

Which statement describes how hand warmers work?

• An endothermic process occurs in which chemical energy is transformed into thermal energy.

• An endothermic process occurs in which thermal energy is transformed into chemical energy.

• An exothermic process occurs in which chemical energy is transformed into thermal energy.

• An exothermic process occurs in which thermal energy is transformed into chemical energy.

Ammonia is oxidised as shown. The platinum is chemically unchanged at the end of the reaction. What is the reason for using platinum?

• to absorb the heat from the reaction

• to filter out oxygen from the air

• to increase the rate of the reaction

• to neutralise the ammonia

Which equation shows iron or one of its compounds being reduced?

• 2FeCl₂ + Cl₂ → 2FeCl₃

• Fe + CuSO₄ → FeSO₄ + Cu

• Fe + H₂SO4_ → FeSO₄ + H₂O

• FeSO₄ + Mg → MgSO₄ + Fe

Which substances react with dilute sulfuric acid to form a salt?

• A

• B

• C

• D

Which statement about Group I elements is not correct?

• Caesium and rubidium are electrical conductors.

• Caesium is softer than lithium.

• Potassium has a higher melting point than rubidium.

• Sodium is more reactive than rubidium.

Sodium is a metal in Group I of the Periodic Table. Some of the properties of sodium are listed.

1 It conducts electricity.

2 It forms white compounds.

3 It forms a basic oxide.

4 It is malleable.

Nickel is a transition metal. Which properties are shown by nickel as well as by sodium?

• 1, 2 and 3

• 1, 2 and 4

• 1, 3 and 4

• 2, 3 and 4

Which reaction does not occur in the blast furnace?

• C + O₂ → CO₂

• C + CO₂ → 2CO

• 4Fe + 3O₂ → 2Fe₂O₃

• Fe₂O₃ + 3CO → 2Fe + 3CO₂

Gases from a car engine pass through the catalytic converter in the exhaust system of the car.

Which gases are at lower concentrations when they leave the catalytic converter?

• carbon dioxide and nitrogen

• carbon dioxide and nitrogen oxides

• carbon monoxide and nitrogen

• carbon monoxide and nitrogen oxides

Which row shows the conditions used for making sulfur trioxide in the Contact process?

• A

• B

• C

• D