explain why R is ACONSTANT IN THE IDEAL GAS EQUATION

Answer 1

This equation was derived from the combined law and Avogadro's law, so if one combines these two, we get:

pv/T = C (C is a constant which is directly proportional
to the nr of moles of gas)

And the proportionality factor so happened to be
R, a constant (8.314472 J·K−1·mol−1)
So if we say C=nR, and rearrange the equation, we get

pV= nRT , our equation.