IGCSE Chemistry

Which statement about liquids is correct?

• They have a fixed shape and a fixed volume.

• They have a fixed shape but not a fixed volume.

• They have no fixed shape but they do have a fixed volume.

• They have no fixed shape and no fixed volume.

Pure copper chloride can be obtained from a mixture of powdered copper and solid copper chloride.

Three stages in the method are listed.

P add water and stir

Q crystallise

R filter

In which order are these stages carried out in order to obtain pure copper chloride from the mixture?

• P → Q → R

• P → R → Q

• R → P → Q

• R → Q → P

A rock contains three ores, galena (PbS), copper pyrites (CuFeS₂) and cinnabar (HgS).

How many metals are present in this rock?

• 3

• 4

• 5

• 8

What is the equation for the complete combustion of ethane?

• C₂H₆ + 2O₂ → 2CO₂ + 3H₂O

• 2C₂H₆ + 3O₂ → 4C + 6H₂O

• 2C₂H₆ + 5O₂ → 4CO + 6H₂O

• 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

What are the products of the electrolysis of concentrated aqueous sodium chloride?

• chlorine, hydrogen and sodium

• chlorine, hydrogen and sodium hydroxide

• chlorine and hydrogen only

• chlorine and sodium only

Which statement describes an exothermic reaction?

• Heat energy is transferred from the surroundings and the temperature decreases

• Heat energy is transferred from the surroundings and the temperature increases

• Heat energy is transferred to the surroundings and the temperature decreases.

• Heat energy is transferred to the surroundings and the temperature increases.

Dilute hydrochloric acid is added to lumps of calcium carbonate. Which change decreases the rate of the reaction?

• Decrease the temperature of the acid

• Increase the concentration of the acid

• Use a larger volume of the acid.

• Use powdered calcium carbonate.

When iron is heated with steam, a black solid is formed.

The equation for the reaction is shown.

iron + water → iron oxide + hydrogen

Which statement about this reaction is correct?

• Iron has been oxidised because it has gained oxygen.

• Iron has been reduced because it removed oxygen from water.

• Iron oxide has been reduced because it contains oxygen.

• Water has been oxidised because it contains oxygen.

Zinc sulfate is made by adding zinc oxide to dilute sulfuric acid.

The steps used to obtain zinc sulfate crystals are listed.

1 filter the solution to remove excess zinc oxide

2 warm the zinc sulfate solution

3 add excess zinc oxide and stir

4 filter and dry the crystals

What is the correct order of the steps?

• 1 → 3 → 4 → 2

• 2 → 1 → 3 → 4

• 3 → 1 → 2 → 4

• 3 → 2 → 1 → 4

During the manufacture of sulfuric acid by the Contact process, sulfur trioxide is produced. The sulfur trioxide is dissolved in concentrated sulfuric acid.

Which statement explains why sulfur trioxide is not dissolved in water?

• The reaction is too endothermic

• The reaction is too exothermic.

• The reaction is too slow.

• The reaction needs a high pressure.