Question

How many liters of oxygen gas at standard temperature and pressure will react with 35.4 grams of calcium metal

Answer 1

1) write and balance the equation
2) convert the g of Ca to moles of Ca
(n=m/MM), n=number of moles, m=mass, MM= molecular mass
3) according to the stoichiometry of the reaction in 1) calculate the moles of O2 needed to react completely with the moles of Ca (n) calculated in 2)
4) convert the moles of O2 to liters of O2 at STP conditions using the molar volume (=22.4L/mol) or the general gas law (PV=nRT)