What does specific heat (Cp) refer to?

Specific heat, denoted as Cp, refers to the amount of heat required to change the temperature of one pound of a substance by one degree Fahrenheit. This concept is essential in thermodynamics and heat transfer, as it helps quantify how much energy is necessary to alter the temperature of a particular substance. Knowing specific heat allows engineers and technicians to calculate energy transfers in heating and cooling processes, which is particularly relevant in industrial applications like ammonia refrigeration.

The other options reflect different heat concepts but do not accurately describe specific heat. The heat needed to freeze a substance is associated with latent heat and phase changes rather than temperature changes per unit mass. The total heat in a system refers to the internal energy, which includes potential and kinetic energies, rather than the specific heat focused on temperature. Lastly, latent heat of vaporization pertains specifically to the energy required for phase changes from liquid to gas or vice versa and does not involve temperature change per unit mass like specific heat does. Thus, option B clearly aligns with the definition and application of specific heat.