Which of the following is the correct SI unit for expressing specific heat?

• A. kg m^2 s^{-2} K^{-1}
• B. J kg^{-1} K^{-1}
• C. J K^{-1}
• D. J mol^{-1} K^{-1}

Answer: (B)

Verified step by step guidance

1. Understand that specific heat capacity is defined as the amount of heat required to raise the temperature of a unit mass of a substance by one degree Kelvin (or Celsius).
2. Recall that the SI unit of heat (or energy) is the joule (J), which can be expressed in base units as \(\mathrm{kg \cdot m^{2} \cdot s^{-2}}\).
3. Since specific heat is heat per unit mass per unit temperature change, its unit should be energy divided by mass and temperature, i.e., \(\frac{\mathrm{J}}{\mathrm{kg} \cdot \mathrm{K}}\).
4. Express this unit explicitly as \(\mathrm{J \cdot kg^{-1} \cdot K^{-1}}\), which matches the correct SI unit for specific heat capacity.
5. Compare the given options and identify that \(\mathrm{J \cdot kg^{-1} \cdot K^{-1}}\) correctly represents specific heat, while the others represent different quantities such as molar heat capacity or just heat capacity.