Consider this question: What is the molarity of KMnO4 in a solution of 0.0908 g of KMnO4 in 0.500 L of solution?

(a) Outline the steps necessary to answer the question

(b) Answer the question

0.0011 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 KMnO₄ = 0.0908 g

and,

V = 0.500 L

Since,

we know,

m = Molecular mass of KMnO₄ = 158 g/mol

using, the above formula to calculate the moles,

n = w / m = 0.0908 g / 158 g/mol = 0.00057 mol

now, calculating the molarity as,

M = n / V = 0.00057 mol / 0.500 L = 0.0011 M.