Agas effuses 1.55 times faster than propane (c3h8)at the
same
temperature and pressure.
what is the mass of the gas?

 The mass of the gas is 18.3 g/mol.

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:

Squaring both sides and solving for

Hence, the molar mas of unknown gas is 18.3 g/mol.

c8h10 is your answerr