We have 30% (w/w) HCl this means :
100 g solution contains 30 g HCl
?? g solution contains 7.5 g HCl
By cross multiplication:
Mass of solution =

= 25 g solution
I’m pretty sure it’s nitrogen and oxygen but i’m not positive
We see from the chemical formula itself that there is 1
mole of F2 for every 1 mole of CaF2, hence the number of moles of CaF2 is also:
moles CaF2 = 1.23 moles
The molar mass of CaF2 is 78.07 g/mol, so the mass is:
mass CaF2 = 78.07 g / mol * 1.23 mol
<span>mass CaF2 = 96.03 grams</span>