Chemistry · Chapter 9

Gas Stoichiometry and Gas Density

Weigh out a solid, run the reaction and catch the gas. Walk the road map one step at a time, from grams to moles to moles to liters.

The road map press Next step to walk it

From grams of solid to liters of gas, with a balloon that grows GAS COLLECTED

Density and molar mass of the gas

Molar mass of the gas
Density, d = PM/RT
Mass of gas made
Density at STP

Density at STP is just molar mass divided by 22.4 L/mol. Away from STP you need the full d = PM/RT.

Set up the run

Working

Step 1
Grams to moles

Mass and volume never connect directly. Both have to pass through moles, and the balanced equation is the bridge.