A student did an experiment to prove that methane gas, CH4, produces carbon dioxide and water when it burns.
Look at the diagram of her experiment.
a)
The limewater turned milky showing that carbon dioxide had been formed.
A small amount of a colourless liquid condensed in boiling tube X. The student said that this proved that burning methane produced water.
The teacher said that the experiment had been set up incorrectly.
The teacher said that the student’s conclusion about water was not valid.
Describe and explain how the student could change how the experiment is set up to prove that water is produced by burning methane.
[2]