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 4.79 g of KBr(s) are
dissolved in 109.00 g of water, the temperature of the solution drops from 22.99 to
21.08 °C.
The heat capacity of the calorimeter (sometimes referred to as the calorimeter
constant) was determined in a separate experiment to be 1.84 1/°C.
Based on the student's observation, calculate the enthalpy of dissolution of KBr(s) in
kJ/mol.
Assume the specific heat of the solution is equal to the specific heat of water.
AH dissolution
kJ/mol
Thermometer
Cardboard or
Styrofoam lid
Nested
Styrofoam cups
Reaction
occurs in
solution.