Question

The combustion of propane (C3H8) in the presence of excess oxygen yields CO2and H2O:C3H8(g) + 5O2(g) 3CO2(g) + 4H2O (g)When 2.5 mol of O2are consumed in thisreaction, __________ mol of CO2are produced.

Answer 1

Answer: 1.5 moles of $CO_2$ are produced.

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

$C_3H_8(g)+5O_2\rightarrow 3CO_2(g)+4H_2O(g)$

According to stoichiometry:

5 moles of oxygen produce = 3 moles of carbon dioxide

Thus 2.5 moles of oxygen produce = $\frac{3}{5}\times 2.5=1.5$ moles of carbon dioxide

Thus 1.5 moles of $CO_2$ are produced.