Heat Capacities: Screencasts

Defines heat capacity, shows how it depends on temperature, and shows how it is used to calculate enthalpy changes.

We suggest that after watching this screencast, you list the important points as a way to increase retention.

Example using physical properties to perform sensible heat calculations. Calculates the heat required to increase the temperature of water vapor from 100°C to 300°C.

We suggest that after watching this screencast, you list the important points as a way to increase retention.

Important Equations:

\[C_V = \left(\frac{\partial U}{\partial T}\right)_V\]

where \(C_V\) is the constant volume heat capacity,
\(U\) is specific internal energy,
\(T\) is temperature, and
\(V\) is specific volume.

\[\Delta U = \int_{T_1}^{T_2} C_VdT \] (not just at constant \(V\) for ideal gas, liquid, or solid)

where \(\Delta U\) is the change in specific internal energy as the system temperature changes from \(T_1\) to \(T_2\).

\[C_P = \left(\frac{\partial H}{\partial T}\right)_P\]

where \(C_P\) is the constant pressure heat capacity,
\(H\) is the specific enthalpy (kJ/mol), and
\(P\) is pressure.

\[\Delta H = \int_{T_1}^{T_2} C_PdT \] (not just at constant \(P\) for ideal gas, liquid, or solid)

Ideal Gas: \(C_P = C_V + R\)

where \(R\) is the ideal gas constant

liquids, solids: \(C_P = C_V\) (approximately)