2. How many grams of sodium fluoride (NaF) are needed to prepare a 0.400m NaF

solution that contains 750 g water? (molar mass of NaF - 42.0 g/mol)

20%

A 18.9 g NaF

OB 9.12 g NaF

c 12.6 g Naf

OD 28.0 g Naf

12.6 g NaF

Explanation:

Recall that 1g of water = 1 ml of water hence the volume of the solution is 750ml

Given that

m/M = CV

m = mass of solute = ?

M = molar mass of solute = 42.0 g/mol

C = concentration of solution = 0.400 M

V=volume of solution = 750ml

m = MCV

m = 42.0g/mol * 0.400 M * 750/1000

m = 12.6 g of NaF