Formula Ideal Gas Pressure    Mass density    RMS velocity

Pressure

Unit
Pressure in a closed system containing an ideal gas.

Mass density

Unit
Mass density is the mass of all gas particles per volume of the gas.

RMS velocity

Unit
Root mean square (RMS) velocity is the mean value of the squared velocities $$v^2$$ of gas particles. So you sum the squared velocities of individual particles and divide by the number of particles, then you get the RMS value. The unit of $$\langle v^2\rangle$$ is $$\frac{\text m^2}{\text s^2}$$.