Question

If the He in Problem 3 takes 20 sec to effuse, how long will NH3 take?

Answer 1

In Graham's law of effusion, the rate of effusion is inversely proportional to the square root of the molar mass of the gas.

The molar mass of NH3 is 17 g/mol.

Let's use the ratio of the square roots of the molar masses of He and NH3 to find the time it takes for NH3 to effuse:

(sqrt(Molar mass of He) / sqrt(Molar mass of NH3)) = sqrt(4 / 17)

So the rate of effusion of NH3 is:

(sqrt(Molar mass of NH3) / sqrt(Molar mass of He)) * (rate of effusion of He) = sqrt(17 / 4) * 3 = 3.67

Therefore, NH3 will take 3.67 times longer to effuse than He.

Time for NH3 = 20 sec × 3.67 = 73.4 sec.

So NH3 will take approximately 73.4 seconds to effuse.

Answer 2

NH3 will take approximately 5.88 seconds to effuse.

To calculate how long NH3 will take to effuse, we can use the formula:

Effusion rate of X = (Molar mass of Y / Molar mass of X)^1/2 * Time for X

Given that He takes 20 sec to effuse, we can substitute the values and solve for NH3:

Effusion rate of NH3 = (Molar mass of He / Molar mass of NH3)^1/2 * Time for He

Let's plug in the values:

Effusion rate of NH3 = (4g/mol / 17g/mol)^1/2 * 20 sec = 5.88 sec

Therefore, NH3 will take approximately 5.88 seconds to effuse.