H2 Chemistry Gas Collection Planning: Displacement of Water and CO2 Volume

Q: Do H2 Chemistry candidates need to carry out gas collection by displacement of water in Paper 4?
A: SEAB 9476 says candidates are not required to carry out gas collection experiments involving displacement of water or gas syringes during the practical examination. However, planning and data-treatment questions can still use gas-collection logic, gas-volume calculations, and apparatus evaluation.

Fast answer for Paper 4
Treat this as a planning and calculation skill: state the apparatus, predict the expected gas volume, check the limiting reagent, describe precautions that prevent gas loss or water backflow, and show how the volume supports a stoichiometric conclusion.

Quick gas-planning map

• This is about whether the gas setup is suitable: Name the apparatus and gas measured.
• Suitability depends on expected volume: Calculate moles of gas, then volume.
• Good planning explains range, gas loss, solubility, and limiting reagent: State precautions and why the chosen vessel fits the predicted volume.

Concrete example: If $\pu{0.00250 mol}$ of carbonate produces $\pu{0.00250 mol}$