Experimental Measurements of the Internal Energy of Non-Ideal Carbon Dioxide

An experimental effort was conducted to measure the change in internal energy of non-ideal carbon dioxide as its volume rapidly expanded with the sudden opening of a valve from one to two compressed gas cylinders. This was achieved by measuring the mass heat capacity of the gas cylinders and the manifold-valve, and measuring the change in temperature from the sudden doubling of volume of the non-ideal carbon dioxide. It was determined that an empirical equation for the change in internal energy of a non-ideal fluid, obtained via earlier measurements of the enthalpy of vaporization for multiple different molecules, was more accurate than previous estimated methods used for estimating the change in internal energy by estimating the change in entropy.