Question

A balloon is filled with 3.8 L of helium gas at STP. Approximately how many moles of helium are contained in the balloon?

Answer 1

Approx. `0.17` `mol`

Explanation:

The molar volume of an ideal gas at `"STP"` is `22.4` `L`. We have a volume of `3.8*L` helium gas under these conditions.

Assuming, quite reasonably, that helium behaves ideally, the molar quantity of helium gas is simply the quotient, `(3.8*L)/(22.4*L*mol^-1)` `=` `??` `"moles"` ?