Gasprop calculates the physical and thermodynamic properties of a natural gas mixture, given the compositional data. You can input the mole percentage composition of each component in the natural gas mixture, such as 85% methane, 10% ethane, etc. and Gasprop will calculate the apparent molecular weight and gravity (relative to air =1.00) of the natural gas mixture, along with other properties such as viscosity, specific heats, Cp and Cv, the ratio Cp/Cv, and the Compressibility factor Z at a specified temperature and pressure. The latter can be calculated using one of the various methods, such as Standing and Katz, AGA method, etc. The built-in database of gas component properties can also be updated by the user.