Argon has a molar mass of 39948gmol Calculate the mass of Ar

Argon has a molar mass of 39.948g/mol. Calculate the mass of Argon in a 1.0L container at 100K and 1.0 atm. (Use 2 sig figs) (Hint: First, calculate the density in g/L, then use this to find the mass in 1.0L)

Solution

PV = nRT

1 x 1 = n x 0.082 x 100

n = 0.12195 mol

Mass = n x molar mass =  0.12195 x 39.948 = 4.872 g