A 0.465 g sample of an unknown compound occupies 245 ml at 298 k and 1.22 atm. what is the molar mass of the unknown compound?

a. 26.3 g/mol

b. 33.9 g/mol

c. 12.2 g/mol

d. 38.0 g/mol

e. 81.8 g/mol

we can find the number of moles of gas using the ideal gas law equation

PV = nRT

where P - pressure - 1.22 atm

V - volume - 0.245 L

n - number of moles

R - gas constant - 0.08206 L. atm/mol. K

T - temperature - 298 K

substituting the values in the equation

1.22 atm x 0.245 L = n x 0.08206 L. atm/mol. K x 298 K

n = 0.0122 mol

molar mass of compound = mass present / number of moles therefore molar mass = 0.465 g / 0.0122 mol = 38.1 g/mol

the answer is d) 38.0 g/mol