Molecular mass of He+MON and He+MMH

hamzaaaa

Dear all

I have a case. I have two tanks, one is filled with Helium gas and monomethylhydrazine(MMH) and another tank with Helium gas and Dinitrogentetraoxide(MON). Both tanks are at 47degC so they are in gaseous form.

I want to know what will be the Molecular Mass of the gas. The molecular mass of He=4 g/mol,MMH=46 g/mol and MON=92 g/mol.

So can anyone tell me what will be the molecular mass i should use for computations for (He+MMH, He+MON and He+MMH+MON)

Thanks

Borek

For some applications you can use weighted average - but calculation requires knowing composition of the mixtures.

hamzaaaa

But why to take the average and why not the sum of all three?

Borek

Because some properties scale as the average of the molar mass.

Solve this problem: you mix 0.5 L He and 0.5 L Ar. What is the density of the mixture?