Specific Heat Capacity [Thermodynamics]

Specific Heat Capacity

Definition :

Specific heat capacity^[1] (c) is an intensive property,^[2] meaning it does not depend on the amount of the substance. It represents the amount of heat needed to raise the temperature of 1.00 kg of a material by 1.00°C (or 1.00 K).

The specific heat capacity is a characteristic property of a substance and is measured in SI units as J/(kg·K) or Cal/(kg·K).

There are two types of specific heats:

Specific heat at constant volume (Cv): The amount of energy needed to raise the temperature of a substance while keeping its volume constant.
Specific heat at constant pressure (Cp): The amount of energy required to raise the temperature of a substance while maintaining constant pressure.

The specific heat at constant pressure (Cp) is always greater than Cv because, under constant pressure, the system expands, requiring additional energy to facilitate this expansion.

For an ideal gas, the universal gas constant R is expressed as:

R = Cp - Cv

Specific heats for solids and liquids (incompressible substances):

R = Cv

Note :

when heat is transferred from a system to its surroundings, the process is exothermic.

when heat is transferred to a system from its surroundings, the process is endothermic

Q_{Total} = \sum Q_{system} = Q_{S 1} + Q_{S 2}