Specific Heat Capacity

The Specific Heat Capacity is the amount of heat required to change a unit mass of a substance by one degree in temperature. The heat supplied to a unit mass can be expressed as

dQ = m c dt (1)
where
dQ = heat supplied (kJ, Btu)
m = mass (kg, lb)
c = Specific Heat Capacity (kJ/kgoC, Btu/lboF)
dt = temperature change (oC, oF)

Expressing Specific Heat Capacity using (1)
c = dQ / m dt (1b)

Converting between Common Units
* 1 Btu/lbmoF = 4186.8 J/kg K = 1 kcal/kgoC

Specific Heat Capacity Gases
There are two definitions of Specific Heat Capacity for vapors and gases:
cp = (δh/δT)p - Specific Heat Capacity at constant pressure (kJ/kgoC)
cv = ( δh/ δT)v - Specific Heat Capacity at constant volume (kJ/kgoC)

Gas Constant
The gas constant can be expressed as
R = cp - cv (2)
where
R = Gas Constant

Ratio of Specific Heat
The Ratio of Specific Heat Capacities is expressed
k = cp / cv (3)

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