1. Imagine you have 50.0 grams of 20°C water in one cup and 100. grams of 20°C water in another cup.  Which sample has water molecules with a greater average kinetic energy?  Which will require more energy to raise its temperature by 10°C?  If the same amount of energy were added to these two water samples, which would get warmer?

2. Imagine that you mix 50.0 grams of 20°C water with 50.0 grams of 100°C­ water.  What would happen to the average kinetic energy of the “warm” (100°C) water molecules?  What would happen to the average kinetic energy of the “cool” (20°C) water molecules?  What is the process, on a molecular level, by which this energy transfer takes place?  What will be the final temperature of the mixture?

3. Imagine that you mix 50.0 grams of 20°C water to 100.0 grams of 100°C­ water.  What will be the final temperature of the mixture? (Hint – this is a weighted average problem, right?)

4. Finally, imagine that you mix 50.0 grams of 20°C water with 50.0 grams of 100°C copper.  What would happen to the average kinetic energy of the “warm” (100°C) copper atoms?  What would happen to the average kinetic energy of the “cool” (20°C) water molecules?  What is the process, on a molecular level, by which this energy transfer takes place?

5. Finally, imagine that you mix 50.0 grams of 20°C water with 50.0 grams of 100°C copper.  Something you may not know: the final temperature of the copper-water “system” will NOT be equal to 60°C.  Make a prediction: Do you expect the final temperature will be greater than or less than 60°C?  LET’S DO IT!

6. Finally, imagine that you mix 50.0 grams of 20°C water with 50.0 grams of 100°C copper.  What does this mean about the capacity for water to take in heat energy compared to the capacity for copper to release that energy?  Without any additional information, could you have predicted the final temperature of the water/copper “system”?