[orgo814]

How do you calculate number density for molecules. For example, for N2 it is 2.5 x 10^19. I know number density is = N/V, where N is molecules and V is volume. Assuming for calculating it, you would assume 22.4 L for standard, and molecules 6.022x10^23. How do I make it unique to N2 tho without knowing any other info except room temperature and pressure

[Borek]

Hard to say without seeing the context. Ideal gas equation comes to mind.

[mjc123]

Why unique to N₂? By Avogadro's law it is the same for all gases - to a first approximation. If you want an accurate value specifically for N₂, you would need an accurate equation of state for N₂, or a table of experimental P,V,T data. Room T and P wouldn't be enough.

[orgo814]

So just avagadro number/22400 cm^3?

[mjc123]

Or, more generally, N/V = N_An/V = N_AP/RT.