The amount of gas referred to in moles is called the number of moles of gas.

Here's why:

* Mole (mol): The mole is the SI unit for the amount of substance. It's a way to measure a large number of particles (like atoms or molecules). One mole contains 6.022 x 10^23 particles (Avogadro's number).

* Gas: A gas is a state of matter where particles are far apart and move freely.

So, when we talk about the amount of gas in moles, we're essentially saying how many sets of 6.022 x 10^23 gas molecules we have.