Final answer:
The fuel value of pentane (C5H12) is calculated by dividing its heat of combustion (ΔH°Comb = −3535 kJ/mol) by its molar mass (72.15 g/mol), resulting in a fuel value of 49.01 kJ/g.
Step-by-step explanation:
To calculate the fuel value of C5H12, or pentane, you need to use the given heat of combustion which is ΔH°Comb = −3535 kJ/mol. This value represents the amount of energy released when one mole of pentane undergoes complete combustion in the presence of excess oxygen to produce carbon dioxide and water. To find the fuel value, which is the amount of energy released per gram of the substance, you would divide the heat of combustion by the molar mass of pentane.
Pentane has a molar mass of approximately 72.15 g/mol (C = 12.01 g/mol × 5 + H = 1.008 g/mol × 12). Calculating the fuel value involves dividing the heat of combustion by the molar mass:
Fuel value of C5H12 = ΔH°Comb / Molar mass of C5H12 = −3535 kJ/mol / 72.15 g/mol = −49.01 kJ/g
This means that the fuel value of pentane is 49.01 kJ/g.