You drop 378 g of solid ice at −35°C into a bucket of water (1,200 g) at 45°C. Eventually, the ice all melts, and the entire system comes into thermal equilibrium. Find the final temperature of the system.

Answer 1

Assume a thermal equilibrium temp. T and find the heat absorbed by ice (say Q1)to raise its temp.from -35 deg. to T deg.

Similarly, find heat released by water (say Q2) when its temp. lowers from 45 deg. to T deg.

Putting Q1 = Q2 will give you T in deg. C.
Note: Do not forget to include the latent heat while computing Q1