Past Paper Questions

Question 1

What colour will methyl orange go when added to a solution of lithium + water

Answer 1

Yellow due to the presence of hydroxide ions

Question 2

Describe a series of tests to determine if a white powder is lithium carbonate

Answer 2

Lithium burns with a red flame
Carbonate will react with HCL to produce carbon dioxide which will turn limewater cloudy

Question 3

What is the ion of nitrate and ammonium

Answer 3

NO3-
NH4+

Question 4

Pair 1 = bromine solution and potassium chloride
Pair 2 = bromine solution and potassium iodide solution
Explain how the student can use the results of these experiments to order reactivity

Answer 4

Reactivity decreases down the halogen group
Bromine is less reactive than chlorine so does not displace the chlorine, therefore no reaction occurs, therefore chlorine is more reactive

Bromine is more reactive than iodine so displaces it, causing the solution to turn brown, showing that bromine is more reactive than iodine

Question 5

When measuring combustion, why should a student immediately read the final mass

Answer 5

Avoid loss of mass by evaporation

Question 6

How can a student remove water from hydrated sodium sulfate

Answer 6

Heat until no further changes in mass

Question 7

Why is ice used in a beaker for a water

Answer 7

Cools the water and causes condensation

Question 8

What is the role of a catalyst

Answer 8

To decrease activation energy by providing an alternate pathway

Question 9

Test for chlorine

Answer 9

Turn damp blue litmus paper white

Question 10

What is the role of the condenser in simple distillation

Answer 10

To cool the vapour causing it to condense out

Question 11

Why is the baseline placed above the solvent in chromatography

Answer 11

So that the samples do not dissolve into the solvent
So that they can travel up the paper

Question 12

aluminium ions

Answer 12

Al3+

Question 13

Test a substance for ammonium ions and carbonate ions

Answer 13

Carbonate and hydrochloric acid react to form carbon dioxide which will turn limewater cloudy

Ammonium reacts with sodium hydroxide to produce a substance that turns damp red litmus paper blue

Question 14

What does a rate of reaction graph of marble chips look like and why

Answer 14

Curve is steepest at the start due to the highest acid concentration
Curve levels off due to the acid being used up