Question

When a solid dissolves in water, heat may be evolved or absorbed. The heat of dissolution (dissolving) can be determined using a coffee cup calorimeter.

In the laboratory a general chemistry student finds that when 4.96 g of NH₄ClO₄(s) are dissolved in 105.40 g of water, the temperature of the solution drops from 23.10 to 19.63 °C.

The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.51 J/°C.

Based on the student's observation, calculate the enthalpy of dissolution of NH₄ClO₄(s) in kJ/mol.

Assume the specific heat of the solution is equal to the specific heat of water.

ΔH_dissolution = ____kJ/mol

Answer 1