4 marksFoundation
Some substances are listed below.
Copper, carbon dioxide, air, sodium chloride.
.1Which substance is an element?
[1 mark] .2Which substance is a mixture?
[1 mark] .3Give the number of different elements in the formula
CaCO3. .4A student has a mixture of sand and water. Choose the best method to get the sand.
[1 mark] 3 marksFoundation
Acids react with metals, bases and carbonates to make salts.
.1Name the salt made when magnesium oxide reacts with hydrochloric acid.
[1 mark] .2Name the salt made when sodium hydroxide reacts with sulfuric acid.
[1 mark] .3Name the gas produced when calcium carbonate reacts with hydrochloric acid.
[1 mark] 3 marksFoundation
Chemical reactions can transfer energy to or from the surroundings.
.1Which two reactions are exothermic? Tick two boxes.
[2 marks] .2Give one everyday use of an endothermic reaction.
[1 mark] 4 marksFoundation
Pure aluminium is soft. Aircraft bodies are made from aluminium alloys.
.1Explain why pure aluminium is soft.
[2 marks] .2Explain why aluminium alloys are harder than pure aluminium.
[2 marks] 3 marksFoundation
A student tests two samples of a white solid. The pure solid melts at 122 °C.
Sample A melts at 122 °C. Sample B melts between 115 °C and 119 °C.
.1Which sample is impure?
[1 mark] .2Give the meaning of a pure substance in chemistry.
[1 mark] .3Which of these is a formulation?
[1 mark] 