Question

In the reaction C + O2 → CO2, 18 g of carbon react with oxygen to produce 72 g of carbon dioxide. What mass of oxygen would be needed in the reaction?
18 g
54 g
72 g
90 g

Answer 1

Hint, that reactions, tell us that 1 mole of Carbon reacts with 1 mol of O2, to gives 1 mol of CO2. Now we have
18/12= 1.5 moles of Carbon,
and
72/44 = 1.636 mol of CO2