Question

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

Answer 1

d) 44 g/mol

Step-by-step 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