First, calculate how many moles of CaF2 are in the solution: 0.8L * 0.62 moles/L = 0.496 moles .

Second, calculate how many grams of CaF2 are in 0.496 moles.

a) molecular weight of CaF2: 40 g/mole +2*18 g/mole = 76 g/mole

b) multiply molecular weight by the number of moles to get the weight of CaF2 in the solution:

76 g/mole x 0.496 moles = 37.696 g