Solve gas stoichiometry problems.
Gas stoichiometry chains two steps. First the mass of limiting reactant becomes moles by dividing by its molar mass. Then the balanced equation's mole ratio converts that into moles of gaseous product. Only at the end does the ideal gas law turn moles into a volume, which is why the answer depends on the temperature and pressure of collection — the same reaction fills a much larger vessel at 500 K than at 298 K.
Mass to gas volume
moles reactant = mass / molar mass; moles product = moles reactant x mole ratio; V = n R T / P
Read it off the balanced equation. Burning methane, CH4 + 2 O2 gives CO2 + 2 H2O, so the ratio of water vapour to methane is 2 and of carbon dioxide to methane is 1.
Divide each reactant's moles by its coefficient; the smallest quotient identifies the limiting reactant. Enter that reactant's mass and molar mass — the calculation assumes the reaction goes to completion on it.
Because textbook answers and gas cylinder specifications are frequently quoted at standard conditions. Comparing the two volumes also shows immediately how much the collection conditions inflate or shrink the result.