W = Area = V f V i P d V ( P f , V f ) ( P i , V i ) The shape of PV diagram depends on the nature of the thermodynamic process. - - - - Unit Heat and thermodynamics is called specific heat capacity at constant volume. If the volume is kept constant, then the supplied heat is used to increase only the internal energy. No work is done by the gas as shown in Figure .
. Figure . Specific heat capacity at constant volume Conductor Gas Q Insulator Pin It implies that to increase the temperature of the gas at constant volume requires less heat than increasing the temperature of the gas at constant pressure. In other words s p is always greater than s v .
Molar Specific heat capacities Sometimes it is useful to calculate the molar heat capacities C p and C v . The amount of heat required to raise the temperature of one mole of a substance by 1K or °C at constant volume is called molar specific heat capacity at constant volume (C v ). If pressure is kept constant, it is called molar specific heat capacity at constant pressure (C p ). the structure and molecular nature of the system.
Unlike solids and liquids, gases have two specific heats: specific heat capacity at constant pressure ( s p ) and specific heat capacity at constant volume ( s v ). . . Specific heat capacity Specific heat capacity at constant pressure ( s p ): The amount of heat energy required to raise the temperature of one kg of a substance by K or °C by keeping the pressure constant is called specific heat capacity of at constant pressure.
When the heat energy is supplied to the gas, it expands to keep the pressure constant as shown in Figure . Figure . Specific heat capacity at constant pressure Conductor Gas Q Insulator In this process a part of the heat energy is used for doing work (expansion) and the