Hey there!:
Molar mass MgCl2 = 95.2110 g/mol
So:
1 mole MgCl2 -------------- 95.2110 g
moles MgCl2 ---------------- 319 g
moles MgCl2 = 319 * 1 / 95.2110
moles MgCl2 = 319 / 95.2110
=> 3.350 moles of MgCl2
Hope that helps!
The formula will be AI2O3
Mass = Density × Volume
= 30.0 mg / mL × 375 mL
= 11250 mg
= 11.25 g
∴ the total mass of insulin in the bottle is 11.25 g (11250 mg)