Question

When a 5.00-g sample of KSCN is dissolved in water in a calorimeter that has a total heat capacity of 3.459 kJ·K–1, the temperature decreases by 0.360 K. Calculate the molar heat of solution of KSCN.

Answer 1

Given data,

Mass of KSCN = 5 g

Total heat capacity = 3.459 kJ/K

Temperature = 0.360 K

moles of KSCN = mass / molar mass

= 5.00 g / 97.1 g / mol

= 0.0514 moles

Heat = Total heat capacity x Temeprature

= 3.459kJ / k x 0.360 K

= 1.245 kJ

Molar heat of solution = Heat / No.ofmoles of KSCN

= 1.245 kJ / 0.0514 moles

= 24.22 kJ / mol

Therefore, the molar heat of solution of KSCN = 24.22 kJ/mol