Question

50g of ice at 0°C is mixed with 50g of water at 80°C, what will be the final temperature of a mixture?

(a) 0°C

(b) 40°C

(c) 60°C

(d) 4°C

The question was posed to me in class test.

The origin of the question is Latent Heat in section Kinetic Theory of Gases of Engineering Physics I

Answer 1

Right option is (a) 0°C

To explain: Heat required to melt 50g ice = mL = 50×80=4000cal

Heat given out by water in cooling from 80°C to 0 = mc∆T=50×1×80=4000cal

Heat given by water is just sufficient to melt the whole ice. So the final temperature is 0°C.