can anyone help me with this one?

Question

A 400 g block of copper at a temperature of 75°C is dropped into 750 g of water at 23°C. The water is contained in a 100 g glass container. What is the final temperature of the mixture?

Answer 1

The copper has a heat value (term?) of 400g*75C = 30K
Water & glass have a heat value of (100g+750g)*23C = 19.55K
Mean heat value is 24.775K
Combined total weight is 1250g
Average final temperature will be 19.82C
Note that temperatures were not above boiling point.
Therefore no losses would occur due to steam.