Final answer:
The substance in question is likely copper, based on its calculated specific heat capacity of 0.39 J/g°C.
Step-by-step explanation:
This problem depends upon the concept of specific heat capacity, which is the amount of heat that is required to increase the temperature of 1 gram of a substance by 1 degree Celsius. We can use the formula q = mcΔT, where q is the amount of heat absorbed (168 J), m is the mass (24 g), c is the unknown specific heat capacity we are solving for, and ΔT is the change in temperature (18 °C).
Applying these values to the formula, we can solve for c: c = q / (m*ΔT) = 168 J / (24g * 18°C) = 0.39 J/g°C. This value matches with the specific heat of copper, so the substance in question might be copper.
Learn more about Specific Heat Capacity