Question

To determine whether a shiny gold-colored rock it actually gold, a chemistry student decides to measure its heat capacity. She first weighs the rock and finds it has a mass of 4.7 g. She then finds that upon absorption of 57.2 J of heat, the temperature of the rock rises from 25 degree C to 57 degree C. Find the specific heat capacity of the substance composite the rock and determine whether the value is consistent with the rock being pure gold by referring to Table

Answer 1

Given

Mass = 4.7 g

Temperature

Initial T1 = 25 C = 298 K                  final T2 = 57 C = 330 K

Energy = m Cp (T2- T1) = 57.2 J

4.7 g * Cp * ( 57 - 25 ) C = 57.2 J

Cp = 0.38 J/g^oC which is not equal to Cp value of Pure gold which is 0.129 J/g^oC

so the rock is not pure gold