Is the Avogadro constant used in the Avogadro's law formula?

1 Answer
Jan 12, 2015

The mathematical expression for Avogadro's law is

Vn=constant, where

V - the volume of the ideal gas;
n - the amount of gas - expressed in moles;

So, what that above equation suggests is that there is a relationship between the volume a gas occupies and how much of that gas is present; this takes place for constant temperature and constant pressure, which, using the ideal gas law, implies that

PV=nRTV=nRTPVn=RTP=constant, since

R, P, and T are all constants in this case.

To answer your question, Avogadro's number is not used in the formula for Avogadro's law; however, it could be, if you take into account the fact that

N=nNA, where

N - the number of molecules of gas present;
n - the number of moles of gas;
NA - Avogadro's number - 6.0221023 molecules/mol

If you multiply the ideal gas equation by NANA on the right-hand side, you'll get

PV=nNANART=nNARNAT=NRNAT,

where RNA=k - Boltzmann's constant = 1.381023 J/K

So, in this form, PV=NkT, so you could write Avogadro's law using

VN=kTP=constant