If a 0.614 g sample of a gas maintains a pressure of 238 mm Hg when contained in a 1.0 L flask at 0.0°C, what is molar mass of the gas? If a 0.614 g sample of a gas maintains a pressure of 238 mm Hg when contained in a 1.0 L flask at 0.0°C, what is molar mass of the gas?

a. 120 g/mol

b. 8.8 g/mol

c. 22 g/mol

d. 44 g/mol

e. 5 g/mol

d) 44 g/mol

Explanation:

If we can consider that this gas behaves like an ideal gas, then we can use the following formula:

PV=nRT

P=pressure

V=volume

n=N° of moles

R = gas constant, it has multiple units, for this case, we will use 62.36 mmHg*Lt/mol*K

Then, the number of moles can also be noted as:

n=m/M, where m=mass and M=molar gas so: PV = (m/M) RT

M = (mRT) / (PV)

And we have the rest of the values for this case:

T=0°=273°K

V=1Lt

P=238 mmHg

m=0.614 g

If we finally put all these values in our formula, we can get the molar mass for this gas:

M = (0.614x62.36X273) / (273x1) gxmmHgxLtx°K/molx°K / (mmHgxLt)

M = 44 g/mol