Isooctane is a good model compound for gasoline. When 1.14 g of isooctane (114 g/mol) reacts with excess oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 10.0oC. The heat capacity of the calorimeter is 5.46 kJ/oC. Determine the molar enthalpy of combustion of isooctane.

Question

Chemistry

Clark Ferrell

3 June, 11:03

Isooctane is a good model compound for gasoline. When 1.14 g of isooctane (114 g/mol) reacts with excess oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 10.0oC. The heat capacity of the calorimeter is 5.46 kJ/oC. Determine the molar enthalpy of combustion of isooctane.

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Micaela Vaughan · Answer 1

-5460 kJ

Explanation:

The heat absorbed by the calorimeter, Qc is given by

Qc = CΔT where C is the specific heat of the calorimeter,

ΔT is the change in temperature

Once we have Qc we will have the negative value of the enthalpy change per 1.14 g (0.01 mol) and we will just calculate the change per mole as the problem requires.

Qc = 5.46 kJ / ºC x 10.0 ºC = 54.6 kJ

ΔH = - 54.6 kJ/0.01mol = - 5460 kJ