Question

How much heat is required to change 2kg of ice at 0C into water at 20C?

Answer 1

Heat required to change 0°C ice to 0°C water, Q1=ml(f)

=2×336000 J

=672000 J

Heat required to change 0°C water t 20°C water, Q2=ms×(theta2-theta1)

=2×4200×20 J

=168000 J

So total required heat,Q=Q1+Q2

=840000 J