If 76 grams of Nal are dissolved in enough water to make 225.0 mL of solution, what is the molarity of the solution? (2.25 mol/L)

2.25 M

Explanation:

Molarity of a substance, is the number of moles present in a liter of solution.

M = n / V

M = molarity

V = volume of solution in liter,

n = moles of solute,

Moles is denoted by given mass divided by the molecular mass,

Hence,

n = w / m

n = moles,

w = given mass,

m = molecular mass.

From the question,

w = given mass of Nal = 76 g

and,

V = volume of solution = 225.0 mL

since,

1 mL = 1 / 1000 L

V = 225.0 / 1000 L = 0.225 L

Since,

we know,

m = Molecular mass of NaI = 149.89 g / mol

using, the above formula to calculate the moles,

n = w / m = 76 g / 149.89 g/mol = 0.507 mol

now, calculating the molarity as,

M = n / V = 0.507 mol / 0.225 L = 2.25 M