Final temperature of a system???

Question

Assume we have a sample of 2 kg of aluminum at 50 degrees C that we put in contact with 4 kg of copper at 0 degrees C. If we assume they are perfectly insulated except for the point of contact what is the final temperature of the system?

Answer 1

You need to know the specific heat capacity of both aluminium and copper.

specific heat capacity of copper = 400 J kg^-1 K^-1

specific heat capacity of aluminium = 900 J kg^-1 K^-1

Let the final temperature be T degree C.

then 0<T<50.

Heat lost by aluminium = heat gained by copper

2 X 900 X (50 - T)   = 4 X 400 X (T - 0)

90 000 - 1800T = 1600T

T = 90 000 / 3400

T = 26.5 degree C. (ans)