Practical questions

You will complete 12 required Specified Practical Activities if you are studying GCSE Chemistry, and 27 if you are studying GCSE Combined Science (nine of these are in Chemistry). These help you develop some key practical techniques in Chemistry.

You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.

There are three Specified Practical Activities in the 'Rate of chemical change and dynamic equilibrium' section:

  • investigation into the effect of one factor on the rate of a reaction using a gas collection method
  • investigation into the effect of one factor on the rate of the reaction between dilute hydrochloric acid and sodium thiosulfate
  • investigation into the effect of various catalysts on the decomposition of hydrogen peroxide

Questions courtesy of Eduqas.

Sample question 1 - Foundation

Question

1.50 g of manganese(IV) oxide powder was accurately weighed and put into 20 cm3 of hydrogen peroxide solution. After the reaction had stopped, the reaction mixture was filtered into a pre-weighed filter paper.

The filtered manganese(IV) oxide and filter paper was dried in an oven.

The mass readings are shown below.

Mass
Filter paper1.26 g
Manganese(IV) oxide and filter paper after drying2.74 g
Recovered manganese(IV) oxide1.48 g

Suggest why not all of the manganese(IV) oxide was recovered and how this problem could be overcome. [2 marks]

  • not all manganese oxide recovered during filtering [1]
  • wash beaker out with water (to retrieve all manganese oxide) [1]

Sample question 2 - Foundation

Question

Trystan carried out an investigation into the reaction between dilute hydrochloric acid (HCl) and magnesium ribbon. He reacted the magnesium with five different concentrations of acid and measured the volume of hydrogen gas produced after 30 seconds.

Name the apparatus Trystan could use to measure the volume of gas produced. [1 mark]

Gas syringe [1]

Sample question 3 - Higher

Question

Trystan carried out an investigation into the reaction between dilute hydrochloric acid (HCl) and magnesium ribbon. He reacted the magnesium with five different concentrations of acid and measured the volume of hydrogen gas produced after 30 seconds.

Trystan initially measured the volume of gas collected in 60 seconds. Explain why he amended his plan after making these measurements. [2 marks]

  • no useful data was collected/30 cm3 of gas collected in most experiments [1]
  • all the magnesium was used up well before 60 seconds/the final volume of gas was collected well before 60 seconds/the reaction was over well before 60 seconds [1]

Sample question 4 - Higher

Question

The following word equation represents the reaction between zinc and dilute hydrochloric acid.

Zinc + hydrochloric acid → zinc chloride + hydrogen

You are asked to carry out an experiment to show how particle size affects the speed of this reaction.

a) Describe how you would carry out the experiment. [2 marks]

b) State how you would make it a fair test. [2 marks]

c) State how you would know which particle size gives the fastest reaction. [1 mark]

a)

  • collect gas, eg in a gas syringe [1]
  • repeat experiment with different particle sizes of zinc [1]

b) Any two from:

  • same mass of zinc
  • same volume of acid
  • same concentration of acid
  • same temperature

[2]

c) The experiment that gives the volume of gas in the shortest time. [1]