Question

Calculate the internal energy change when 2 moles of water at 0 degrees converts into ice at 0-degree centigrade?

(a) 12 KJ per mole

(b) 6 KJ per mole

(c) 1 KJ per mole

(d) 102 KJ per mole

This question was posed to me in a national level competition.

My question comes from Thermodynamics in section Thermodynamics of Chemistry – Class 11

Answer 1

Correct option is (a) 12 KJ per mole

Easiest explanation: Energy change when 1 mol of water at 0-degree centigrade changes into ice at 0 degrees in centigrade is 6 kJ/mol, So the internal energy change when 2 moles of water at 0 degrees converts into ice at 0 degrees is 12 kJ/mole.