Now, the only problem in this top portion is that we want to go from a proportionality sign to an equal sign. The way we adjust this guy, this top guy, so that we can equal them is by multiplying our right side or adjusting our right side by some constant R.
This is known as the ideal gas constant. So what problem remains? What is R? So, from experimental results, data shows that a temperature of zero Celsius and a pressure of one ATM and any 1 Mol of any gas will give us 22.4 liters of volume. And that means we have four unknowns.