If the density of an unknown gas Z 4.50 g/L at STP, what is the molar mass of gas Z?

1 Answer
May 17, 2016

P.MM= d.R.T

Explanation:

Use the ideal gas equation

P.V=n.R.T

P.V= m/(MM).R.T

P.MM= m/V.R.T

P.MM= d.R.T

P" is the pressure of the gas (" atm")"
MM" is the molar mass ("g.mol^-1")"
d" is the density of the gas ("g.L^-1")"
R" is the universal gas constant ("0.0821*L.\atm.mol^-1.K^-1")"

Solve for MM

MM= (d.R.T)/P

MM=(4.50*g*L^-1* 0.0821*L*atm*mol^-1*K^-1*273*K)/(1.00*\atm)

MM ~= 101" "g.mol^-1