Question

one piece of iron, specific heat capacity of 0.450 J/g•˚C, has a temperature of 129˚C. Another piece of iron has a mass exactly double the mass of the first piece, and its temperature is 45˚C. Both pieces are put inside a calorimeter that has negligible heat capacity. Calculate the final temperature of the calorimeter and its contents.

Answer 1

The long way to calculate it is:

Remember, energy given up by the hot iron = energy gained by the cold iron.

Call the mass of the hot iron X. Mass of the cold iron = 2X

For sensible heat, energy = mass * specific heat * temperature change

Let T be the final temperature

X * specific heat * (129C - T) = 2X * specific heat * (T - 45C)

YouC can cancel X as it's on each side and you can cancel the specific heat as it's on each side

(129C - T) = 2 * (T - 45C)

129C - T = 2T - 90C

219C = 3T

T = 73C