Question

The rate of effusion of an unknown gas was measured and found to be 55.4 mL/min. Under the same conditions, the rate of effusion of O2 is found to be 51.8 mL/min. Which of the following could be the unknown gas? N2

CO
N2O
C2H2
none of these

Answer 1

Answer:
`N_2` or
`CO`.

Step-by-step explanation:

To calculate the rate of diffusion of gas, we use Graham's Law.

This law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows:

`\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}`

`(Rate_(X))/(Rate_(O_2))=\sqrt{(M_(O_2))/(M_(X))}`

`(55.4ml/min)/(51.8ml/min)=\sqrt{(31.9988)/(M_(X))`

Squaring both sides and solving for
`M_(X)`

`M_(X)=28.0g/mol`

Hence, the molar mas of unknown gas is 28.0 g/mol and the gas could be
`N_2` or
`CO`.