Question

In the ideal gas law equation, `PV=nRT`, what is the value of the variable `'R'`?

Answer 1

The Gas constant `R` changes according to the units you employ.

Explanation:

Chemists typically deal with `"litre"` quantities of gases, and typically measure `"pressure"` in units of `"atmospheres"`. Of course, both physicists and chemists tend to use `"degrees Kelvin"` as units of absolute temperature (mind you, there is a `"Rankin"` scale).

Given this, for chemists, `R` is typically used as `0.0821*L*atm*K^-1*mol^-1`. There are other conventions, notably, `R=8.31*J*K^-1*mol^-1`, which requires volumes in `m^3`. All of the gas constants, and their units, should be supplied to you in an exam as supplementary material.