Question

The molar mass of argon is 40g / mol what is the molar mass of a gas if it effuses at 0.91 times the speed of argon gas

Answer 1

To determine the molar mass of the unknown gas, we use Graham's Law of Effusion where it relates the effusion rates of two gases with their molar masses. It is expressed as r1/r2 = √M2/M1. We calculate as follows:

Let 1 = argon gas
      2 = unknown gas

r2 = 0.91r1
r1/r2 = 1/0.91

1/0.91 = √M2/M1 = √M2/40
M2 = 48.30 g/mol