### Chapter 8 HMWK Problem 8.21 Clarification

Posted:

**Sun Jan 22, 2017 4:21 pm**The question is stated as follows:

Question: A piece of copper of mass 20.0 g at 100.0 degrees Celsius is placed in a vessel of negligible heat capacity but containing 50.7 g of water at 22.0 degrees Celsius. Calculate the final temperature of the water. Assume that no energy is lost to the surroundings.

Problem: I know that the heat lost by the metal is equal to the heat gained by the water. Therefore, I said that -q=qH20. Although I got the same answer as in the solutions manual, it stated that the heat lost by the metal is equal to the negative heat gained by water (qmetal=-qH20). Is either interpretation considered valid, or is there a flaw with my reasoning? I've had the same issue with several other problems as well.

Thanks in advance!

Question: A piece of copper of mass 20.0 g at 100.0 degrees Celsius is placed in a vessel of negligible heat capacity but containing 50.7 g of water at 22.0 degrees Celsius. Calculate the final temperature of the water. Assume that no energy is lost to the surroundings.

Problem: I know that the heat lost by the metal is equal to the heat gained by the water. Therefore, I said that -q=qH20. Although I got the same answer as in the solutions manual, it stated that the heat lost by the metal is equal to the negative heat gained by water (qmetal=-qH20). Is either interpretation considered valid, or is there a flaw with my reasoning? I've had the same issue with several other problems as well.

Thanks in advance!