Question

How many liters of solution are needed to make a 3.75 M solution with 38.6 g of magnesium iodide?

Answer 1

$n=m/M$ , n - chemical amount of substance; m - mass of substance; M - molar mass of substance.

The molar mass of MgJ₂ is 278,1g/mol (M(Mg)=24,3g/mol, M(J)=126,9g/mol: 24,3+126,9*2=278,1).

n=38,6g/278,1g/mol=0,139mol

$c=n/V$ , c - solution molarity, n - chemical amount of substance, V - solution volume.

express the desired value: $V=n/c$ .

V = 0,139mol/3,75mol/l=0,037l.

Answer: 0,037L.