Question

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. when 18.0 g of carbon were burned in the presence of 62.3 g of oxygen, 14.3 g of oxygen remained unreacted. what mass of carbon dioxide was produced?

Answer 1

C + O2 --> CO2

18g C = 18/12.01 = 1.49 moles (Limiting Reagent) 
62.3-14.3 = 48g oxygen that reacted 
48g O = 3 moles