How many grams of o2 are in 5.0 mol of the element? can someone tell me if i have this right .? 1 mole of o2 = molecular wt of 32
so 5 mol = 32 *5=160 g

To convert the number of moles into units of mass, we need to know the molecular weight of oxygen which has units of grams per mole. For O2, the molecular weight would 32 grams / mole. We calculate as follows:

5.0 mol O2 ( 32 g / 1 mol ) = 160 g of O2 is present