Since specific heat of a gas depends very much on how a process of changing its temperature is performed, there are specific heat of gases kept at constant temperature ($c_P$) and at constant volume ($c_V$), where some values are given as follow.
| Gas | $c_P$ (kcal/kg $\cdot$ C$^\circ$) | $c_V$ (kcal/kg $\cdot$ C$^\circ$) |
|---|---|---|
| Steam ($100 ^\circ \rm C$) | 0.482 | 0.350 |
| Oxygen | 0.218 | 0.155 |
| Helium | 1.15 | 0.75 |
| Carbon dioxide | 0.199 | 0.153 |
| Nitrogen | 0.248 | 0.177 |
Notice that $c_P$ is always greater than $c_V$ for gases. This distinction is usually negigible for liquids and solids.
- Douglas C. Giancoli, “Physics: Principles with Applications”, Pearson Education Inc., Boston, 7th Edition, Dec 2013, p. 394, url https://isbnsearch.org/isbn/9780321625922.