What is the specific heat capacity of zinc if it requires 146 J to raise the temperature of 15 grams of zinc by 16.2°C? Select one: a. 0.60 J/g°C b. 0.23 J/g°C c. none of these d. 0.39 J/g°C e. 2.5 J/g°C
The Correct Answer and Explanation is:
To calculate the specific heat capacity of zinc, we apply the formula:
Q=mcΔTQ = mc\Delta T
Where: • Q is the heat energy absorbed (146 J) • m is the mass of the substance (15 g) • ΔT is the change in temperature (16.2°C) • c is the specific heat capacity, which we are solving for
Rearranging the formula to isolate c, we get:
c=QmΔT=146 J15 g×16.2 °C=146243≈0.60 J/g°Cc = \frac{Q}{m \Delta T} = \frac{146\ \text{J}}{15\ \text{g} \times 16.2\ \text{°C}} = \frac{146}{243} \approx 0.60\ \text{J/g°C}
Correct answer: a. 0.60 J/g°C
Explanation:
Specific heat capacity is a material’s thermal fingerprint. It tells us how much energy is needed to raise the temperature of a unit mass of a substance by one degree Celsius. To determine this value for zinc, we’re provided with three critical parameters: the total heat energy added (Q), the mass of the sample (m), and the change in temperature (ΔT).
Multiplying 15 grams by a 16.2°C temperature rise gives 243 g°C. Dividing the 146 joules of heat by this product yields approximately 0.60 J/g°C. This value means that every gram of zinc absorbs 0.60 joules of energy for each degree Celsius of temperature increase. That relatively low value reflects zinc’s limited ability to store thermal energy compared to substances like water, which has a much higher specific heat capacity.
Understanding specific heat is crucial in fields such as metallurgy, engineering, and chemistry. It influences thermal conductivity, energy efficiency, and material choice in heat-related applications. For example, zinc’s low specific heat makes it ideal for applications that require quick heating and cooling cycles, such as die casting or galvanization.
Let me know if you’d like a comparison with other metals like copper or aluminum. I’d be happy to add some thermodynamic context.
