Chemistry 5070 · O Level · Air quality and climate

Air quality and climate — practice question

A student tries to work out the percentage of oxygen in air by using the apparatus shown.
(a)[1]

Why is copper used in excess?

(b)[1]

Why is the gas cooled to room temperature before the final volume is measured?

(c(i))[3]

Plot the data on the graph and draw a line of best fit.

(c(ii))[1]

Circle the anomalous point on the graph.

(c(iii))[1]

Suggest a reason for the anomalous result.

(d(i))[1]

Using your graph, determine the final gas volume when the initial volume is $100\text{ cm}^3$.

(d(ii))[1]

Using your answer to (d)(i), calculate the percentage of oxygen in the air.

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: So that all of the oxygen in the air reacts

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI