Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure. For which gas do the molecules have the highest average velocity? a) He
b) Cl2
c) all gases the same
d) NH3

a) He

Explanation:

The formula of average velocity of a gas, v, is:

Where R is gas constant, T is temperature and M is molecular mass of the gas.

As you can see in the formula, the gas with the lowest molecular mass will be the gas with highest average velocity.

Molecular mass of He is 2g/mol; Cl₂ = 70g/mol; NH₃ = 17g/mol.

That means the gas with the highest average velocity is:

h let me think

1.43 x 10^-11 j the guy commented the awnser just making sure u see it .