Chem
posted by rory .
Sulfuric acid, H2SO4, reacts with CaF2 according to:
CaF2 + H2SO4 > CaSO4 + 2 HF
What is the minimum amount, in g, of impure H2SO4 (which is 83.5% H2SO4 by mass) that would be required to produce 16.2 g of HF when reacted with excess CaF2 ?
Could someone walk me through the steps?

calculate the moles of HF from the mass.
calculate the moles of sulfuric acid needed (1/2 the moles of HF).
calculate the mass of sulfuric acid from the moles of sulfuric acid.
divide by .835