Question

A mixture contains 30% of A with Heat Capacity 10 J/^oC, 30% of B with Heat Capacity 20 J/^oC, and 40% of C with Heat Capacity 35 J/^oC, what is the Heat Capacity of mixture?

(a) 14 J/^oC

(b) 17 J/^oC

(c) 19 J/^oC

(d) 23 J/^oC

I have been asked this question in an international level competition.

Question is taken from Heat of Solution, Dissolution and Mixing topic in chapter Energy Balances that Include the Effects of Chemical Reaction, Ideal Processes, Efficiency and the Mechanical Energy Balance and Heats of Solution and Mixing of Basic Chemical Engineering

Answer 1

The correct option is (d) 23 J/^oC

Easiest explanation: Heat capacity of mixture = 0.3*10 + 0.3*20 + 0.4*35 = 23 J/^oC.