# Compute the density of water¶

When converting between mole fraction and concentrations, it is necessary to multiply by the number density of the solvent. Water is often used as a solvent, and the `eqtk.water_density()`

function offers calculation of the density of pure water at atmospheric pressure for various temperature using the IAPWS-95 standards.

The use specifies the temperature in degrees Kelvin and the units for the density.

```
>>> eqtk.water_density(T=293.15, units='M')
55.408916789969595
```