When 150 mL of 0.5 M HCl and 150 mL of 0.5 M NaOH are mixed in a calorimeter, the temperature of the mixture rises by 2 K . If the enthalpy of neutralization of a strong acid with a strong base is -56 kJ mol ⁻¹ and the specific heat capacity of the solution is 4.2 J g ⁻¹ K ⁻¹ , the heat capacity of the calorimeter is ______ J K ⁻¹ . (Assume the density of the solution to be 1.0 g mL ⁻¹ )

Step-by-step solution

Moles of H^+ from HCl = 150 10⁻³ 0.5 = 0.075 mol Moles of OH^- from NaOH = 150 10⁻³ 0.5 = 0.075 mol Heat released during neutralization = 0.075 56 10^3 = 4200 J Total volume of solution = 150 + 150 = 300 mL Mass of solution = 300 g (since density is 1.0 g mL ⁻¹ ) Heat absorbed by the solution = m s T = 300 4.2 2 = 2520 J Heat absorbed by the calorimeter = Total heat released - Heat absorbed by solution = 4200 - 2520 = 1680 J Heat capacity of the calorimeter = 1680 T = 1680 2 = 840 J K ⁻¹ Answer: 840