The rate of diffusion of a gas is primarily determined by its molecular weight. According to Graham's Law of Diffusion, the rate of diffusion of a gas is inversely proportional to the square root of its molecular weight.

Therefore, gases with similar molecular weights will diffuse at similar rates.

Here's why nitrogen (N2) is a good example:

* Nitrogen's molecular weight is 28 g/mol.

To find a gas that diffuses at the same rate as nitrogen, we need to find another gas with a molecular weight close to 28 g/mol.

Some examples include:

* Carbon monoxide (CO): Molecular weight = 28 g/mol

* Ethylene (C2H4): Molecular weight = 28 g/mol

Important Note: These are just a few examples. There could be other gases with molecular weights very close to 28 g/mol that would also diffuse at approximately the same rate as nitrogen.