Determination of the calorific value of olive oil with a demonstration calorimeter

Fats represent the most energy-rich group of the foods which are vital for the human organism. The mean physiological calorific value of fats is about 38.8 kJ/g. Apart from the supply of energy, however, the significance of fats lies also in the transport and resorption of fat-soluble vitamins and in the enhanced flavour of our dishes.
In experiment C6.1.4.1, the calorific value of olive oil is determined. For this purpose, olive oil is burned in an O₂ atmosphere and the temperature rise is measured in the calorimeter. A filament is used to ignite the oil. The energy released is calculated using either a previously determined heat capacity of the filled calorimeter or the individual theoretical values of the heat capacities of the glass jacket and calorimeter liquid. The quantity of heat Q is calculated according to the following formula:

Here DT represents the temperature difference, m_k and m(H₂O) are the mass of the calorimeter and of the water, and C_k and C(H₂O) are the heat capacities of the glass apparatus and the water. In order to calculate the heat of combustion DH, the ignition energy, which also contributed to the heating of the apparatus, must be subtracted. The quantity of heat is then expressed relative to one mol of substance.