The density (in g/L) of helium (He) gas at 723 torr and 225 K is?

How many g/L ?

1 Answer
Oct 23, 2017

rho=0.2*g*L^-1ρ=0.2gL1

Explanation:

Now PV=nRTPV=nRT.....and thus P/(RT)=n/V=("mass"/"molar mass")/VPRT=nV=massmolar massV

And so P/(RT)xx"molar mass"="mass"/V=rho_"helium"PRT×molar mass=massV=ρhelium as required...

ANd we assume of molar quantity of 1*mol1mol under the given conditions....

rho_"helium"=((723*"Torr")/(760*"Torr"*atm^-1)xx4.003*g*mol^-1)/(0.0821(L*atm)/(K*mol)xx225*K)ρhelium=723Torr760Torratm1×4.003gmol10.0821LatmKmol×225K

=0.206*g*L^-1=0.206gL1