How many liters of oxygen gas can react with 84.0 grams of lithium metal at standard temperature and pressure? Show all of the work used to find your answer. 4Li + O2 yields 2Li2O

From the equation:

4mol Li react with 1 mol O2

Molar mass Li = 7g/mol

mol in 84g Li = 84/7 = 12 mol Li

From the equation - 12 mol Li will react with 3 mol O2

At STP 1 mol O2 has volume = 22.4L

At STP 3 mol O2 has volume = 3*22.4 = 67.2L O2 gas will react.