Answer:
12g/mol
Explanation:
At STP, the value of temperature and pressure is 273.15K and 1.0atm respectively.
Data
T = 273.15
P = 1.0 atm
V = 22.0L
m = 12.0g
R = 0.082L.atm / mol.K
From ideal gas equation,
PV = nRT
But n = number of moles = mass (m) / molar mass (M)
n = m / M
PV = mRT/ M
M = mRT / PV
M = (12.0 * 0.082 * 273.15) / (1.0 * 22.4)
M = 268.7796 / 22.4
M = 11.999g = 12g/mol
The molar mass of the gas is 12g/mol
