Question

A 50.0-gram block of copper at 10.0°C is carefully lowered into 100.0 grams of water at 90.0°C in an insulated container. Which statement describes the transfer of heat in this system?
(1) The water loses heat to the block until both are at 10.0°C.
(2) The block gains heat from the water until both are at 90.0°C.
(3) The water loses heat and the block gains heat until both are at the same temperature that is between 10.0°C and 90.0°C.
(4) The water gains heat and the block loses heat until both are at the same temperature that is between 10.0°C and 90.0°C.

Answer 1

First consider and take note of the following: 
1. When 2 or more finite amounts of substances are mix together (with different temperature) the final temperature is never equivalent to the initial temperature of any of the substances involved. 
2. The substances meet at an equilibrium temperature. 
3. Heat transfers from a higher temperature to a lower temperature. 

Only choice (3) satisfies the conditions.