The gas laws in code

You will write three small functions for an ideal gas. Each one uses $pV = nRT$ in SI units.

The idea. Pressure in pascal, volume in cubic metres, temperature in kelvin and $R = 8.31$ J/(mol K). For a fixed amount of gas, $p_1V_1/T_1 = p_2V_2/T_2$.

Your tasks.

1. In pressure, return the pressure in Pa of n moles in a volume V in m³ at a temperature T in K.
2. In new_volume, a fixed amount of gas goes from (p1, V1, T1) to a new pressure p2 and temperature T2. Return the new volume.
3. In density, return the density in kg/m³ of a gas of molar mass M in kg/mol.