Question

If a gas effuses at 4.25 times faster than iodine gas, what is its molar mass?

a. 63.5 g/mol
b. 128 g/mol
c. 42 g/mol
d. 30 g/mol

Answer 1

According to Graham's law of effusion, a gas effusing 4.25 times faster than iodine gas will have a molar mass of 63.5 g/mol.The correct option is A.

Step-by-step explanation:

According to Graham's law of effusion, the rate of effusion of a gas is inversely proportional to the square root of its molar mass. So, if a gas effuses 4.25 times faster than iodine gas, its molar mass will be 1/√4.25 times the molar mass of iodine gas.

The molar mass of iodine gas (I₂) is 253.8 g/mol. Therefore, the molar mass of the unknown gas can be calculated as (253.8 g/mol) / √4.25 = 63.5 g/mol.

Therefore, the correct answer is a. 63.5 g/mol.