This is a lesson with grades D to B on molar gas volumes for AS Chemistry. The hook for the starter is to consider different types of fire extinguisher. Students then consider how they would calculate the volume of carbon dioxide produced from a CO2 extinguisher and 4 extinguishers that contain a solid that decomposes on heating to produce CO2. There is an A grade extension question as well as exam questions with mark schemes. Please rate this resource and leave feedback.