A hydrocarbon fuel is burned with air. Assume the air to be a simple mixture of 21% O₂ and 79% N₂. On a dry basis (all the water vapor has been removed from the products), a volumetric analysis of the products of combustion yields the following:

CO₂: 7.8%,
CO: 1.1%,
O₂: 8.3%,
N₂: 82.8%.

Determine the following:

A. The composition of the fuel on a mass basis

B. The percent theoretical air

C. The air–fuel ratio by mass