Question

>in an effusion experiment, it was determined that nitrogen gas, n2, effused at a rate 1.812 times faster than an unknown gas. What is the molar mass of the unknown gas? Express your answer to four significant figures and include the appropriate units.

Answer 1

Answer: Molar mass of unknown gas will be 45.966 amu.

Explanation: Rate of effusion of a gas can be explained by Graham's Law

Graham's Law: This law states that the rate of effusion of gas is inversely proportional to the square root of the molar mass of the gas.

$\text{(Rate of effusion)}_A=\frac{1}{\sqrt{\text{Molar mass}_A}}$

According to the question,

Rate of effusion of $N_2\text( gas}=1.812\times \text{Rate of effusion of unknown gas}$

$\frac{1}{\sqrt{\text{Molar Mass of }N_2}}=1.812\times\frac{1}{\sqrt{\text{Molar Mass of unknown gas}}}$

Mass of $N_2$ gas = 14 amu

Putting molar mass of $N_2$ in above equation

$\frac{1}{\sqrt{14}}=1.812\times\frac{1}{\sqrt{\text{Molar Mass of unknown gas}}}$

${\sqrt{\text{Molar Mass of unknown gas}}}=1.812\times{\sqrt{14}}$

Squaring both the sides, we get

${\text{Molar Mass of unknown gas}}=(1.812)^2\times 14$

Molar Mass of unknown gas = 45.966 amu.

Answer 2

Answer:

(1.812)^2 x 28 = 91.933632

=91.93 g/mol

Explanation:

The other explanation is correct but the mm of N2 is 28 not 14