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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Maths___Man on May 01, 2021, 02:09:57 AM

Title: Why does a diatomic gas has only half the volume?
Post by: Maths___Man on May 01, 2021, 02:09:57 AM

Like one mole of a diatomic gas has a volume of 11.2l but a monoatomic gas has 22.4l volume?

Title: Re: Why does a diatomic gas has only half the volume?
Post by: Borek on May 01, 2021, 03:15:44 AM

This is not correct, or at least is worded in an incorrect and confusing way.

But let's start from the beginning: do you know Avogadro's principle?

How many molecules of gas in one mole of the monoatomic gas?

How many molecules of gas in one mole of the diatomic gas?

How many atoms of gas in one mole of the monoatomic gas?

How many atoms of gas in one mole of the diatomic gas?

Title: Re: Why does a diatomic gas has only half the volume?
Post by: sjb on May 01, 2021, 07:41:44 AM

Compare https://www.reddit.com/r/chemhelp/comments/n2deqr/why_volume_occupied_by_one_mole_of_diatomic_gas/

Title: Re: Why does a diatomic gas has only half the volume?
Post by: Orcio_87 on May 01, 2021, 05:02:28 PM

@Maths___Man

Volume of gas doesn't depend on it is mono-, di- or tri-atomic, but it is given by equation:

pV = nRT

That means that volume (V) (or pressure - p) of gas increases with its quantity (n) and temperature (T) (R is gas constant).

Structure of gas molecules is not important.