So this is what we want to find. And we want to find this guy and use that to find our grams per mole or molar mass. Because remember, molar mass is the amount of mass per 1 mol. So let's plug these guys in into this equation and we got this by rearranging this, by bringing all these guys on this side. So we got that. So we plug in our atmosphere pressure zero point 13 ATMs over our constant times, our temperature times I or one.