A 56.3g sample of water was heated to 51.2 C and added to 45.8 g of 20.3 C water in a calorimeter, calculate the final temperature of the resulting solution.

Okay I can do that... 37.3 C

But then assume the final temp were 34.7 C instead.
How much heat was lost to the calorimeter?
Calculate the heat capacity.
And for the calorimeter.

I'm not sure where to begin. Thanks in advance.

would the first part be simply 51.2-34.7=16.5 heat lost?