When 4.00 g of KCl(s) (molar mass 74.55 g mol⁻¹) is dissolved in 100.0 g of water in…
CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics
Problem
When 4.00 g of KCl(s) (molar mass 74.55 g mol⁻¹) is dissolved in 100.0 g of water in a coffee-cup calorimeter, the temperature drops from 25.00 °C to 23.50 °C. Assume the specific heat capacity of the solution is 4.18 J g⁻¹ °C⁻¹ and the final solution mass equals the sum of the component masses. What is the molar enthalpy of dissolution, ΔH₍diss₎, of KCl? (Report to the nearest 0.1 kJ mol⁻¹.)
(a) +24.3 kJ mol⁻¹
(b) –12.1 kJ mol⁻¹
(c) +12.1 kJ mol⁻¹
(d) +6.3 kJ mol⁻¹