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 1.44 g of CuSO4(s) are dissolved in 106.40 g of water, the temperature of the solution increases from 24.05 to 25.58 °C.The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.60 J/°C.Based on the student's observation, calculate the enthalpy of dissolution of CuSO4(s) in kJ/mol.Assume the specific heat of the solution is equal to the specific heat of water.

Answer 1

Step-by-step explanation:

Heat absorbed by calorimeter = 1.6 x ( 25.58-24.05) = 2.448 J

Heat absorbed by solution = 107.84 x 1 x ( 25.58 - 24.05 ) = 164.99 J

mol of copper sulphate dissolved = 1.44/159.5 = 9.028 x 10⁻³.

[ Mol weight of copper sulphate is 159.5]

heat evolved by dissolution of 9.028 x 10⁻³ mol is 164.99 + 2.448 = 167.438 x 10⁻³ kJ

Heat evolved per mol = 167.438 x 10⁻³ / 9.028 x 10⁻³ = 18.55 kJ /mol