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11. 600 J of heat energy are transferred to a system that does 400 J of work. By how much does the system's thermal energy change?

12. 200 g of an unknown metal is heated to 90.0 C, then dropped into 50.0 g of water at 20.0 C in an insulated container. The water temperature rises within a few seconds to 27.7 C, then changes no further. Identify the metal.

13. Your 500 mL diet soda, with a mass of 500 g, is at 20 C, room temperature, so you cool it by adding 100 g of ice from the -20C freezer. Does all the ice melt? If so, what is the final temperature? If not, what fraction of the ice melts? Assume that you have a well-insulated cup.