Pentan-1-ol (C5H11OH\text{C}_5\text{H}_{11}\text{OH}C5H11OH) is a straight-chain alcohol being evaluated as a potential sustainable biofuel. An experiment was carried out using a simple copper calorimeter to determine the enthalpy of combustion of pentan-1-ol, as shown in the diagram below.
When 1.42 g of pentan-1-ol was burned, the temperature of the 120.0 g of water inside the copper calorimeter increased by 38.2 ∘C38.2\ ^\circ\text{C}38.2 ∘C. The specific heat capacity of water is 4.18 J K-1 g-1.
Calculate a value for the enthalpy of combustion, in kJ mol−1\text{kJ mol}^{-1}kJ mol−1, of pentan-1-ol. Show your working.
The standard enthalpy of combustion of pentan-1-ol is -3329 kJ mol-1. Suggest three reasons why the experimental value obtained from this calorimetry experiment is much less exothermic.