If 100. grams of liquid water at 100.°C and 200. grams of water at 20.0°C are mixed in an insulated container, what will the final temperature of the mixture be? (Sp. heat of H2O = 4.18 J/g•°C)
a. 46.7°C
b. 60.0°C
c. 66.7°C
d. 73.3°C
e. 77.8°C
Answer: A