Question

An 65.73 g sample of aluminum is placed on a 56.35 g sample of copper initially at 111.86^oC. If the heat is only transferred between the metals (with no loss to the surroundings) and the final temperature of both metals is 36.38^oC, what is the inital temperature (in ^oC) of aluminum?

Answer 1

The temperature of copper has decreased from 111.86^oC to 36.38^oC. It implies copper has the thermal energy (heat) and Al has gained.

The Thermal energy gained by Al = Thermal energy lost by Cu

Energy lost by Cu (Q) = Mass of Cu X heat capacity X temperature difference

Q = 56.35g X 0.385 J/g/oC X ( 36.38^oC - 111.86^oC)

Q = - 1637.5 J

minus sign ndicates energy is lost by Cu

Heat gained by Al = 1637.5 J= 65.73g X 0.902 j/goC X (36.38^oC - T_i)

T_i = initial temperature of Al

(36.38^oC - T_i) = 27.61^oC

T_i = 36.38^oC - 27.61^oC = 8.76 ^oC.