Question

In an experiment, 1.75 g sample of acetic acid, CH3COOH, was burned in oxygen in a calorimeter. The calorimeter contained 925g of water and had a heat capacity of 2.53 kJ/°C. the temperature of the calorimeter and its contents increased from 22.2°C to 26.5°C. use these data to determine the molar heat of combustion of acetic acid? (specific heat capacity of water = 4.18 kJ/Kg·°C) Show ALL Work

Answer 1

First, we determine the amount of energy released by the combustion of the given amount of acetic acid, which can be calculated using:
Energy = mass * specific heat capacity * change in temperature
Q = 925 * 4.18 * (26.5 - 22.2)
Q = 16,626 Joules = 16.6 kJ

Now, the amount of acetic acid available was 1.75 grams. We convert this into moles using:
Moles = mass / molecular mass
Moles = 1.75 / 60
Moles = 0.03 mol

The heat of combustion is:
16.6/0.03
553.3 kJ per mole