Answer:
There are 30. mol O atoms in 2.5 mol Al2(SO4)3
Step-by-step explanation:
The chemical formula for aluminum sulfate, Al2(SO4)3, tells us that in one mole of the compound, there are twelve moles of O atoms (4 × 3 = 12).
2.5 mol Al2(SO4)3 × 12 mol O/1 mol Al2(SO4)3 = 30. mol O to two significant figures