Question

How many mL of oxygen gas will remain in the reaction vessel when 82.4 mL of carbon monoxide gas reacts with 80.0 mL of oxygen gas to form carbon dioxide under constant pressure and tempature?

Answer 1

2 CO (g)   + O2 (g)    ---------------> 2 CO2 (g)

2                  1                                    2

82.4             80.0                                  

here limiting reagent is CO.

2 mol CO   -----------> 1 mol O2

82.4 ml CO   ----------->   ??

moles of O2 required = 82.4 x 1 / 2 = 41.2 mL

remaining O2 = 80.0 - 41.2

volume of oxygen gas remain = 38.8 mL