Question

What is the molarity of a 500 mL of solution made from 80g of NaOH and water?

Answer 1

Molarity= Moles of solute/Volume of solution(in litres)

Solute:NaOH

Moles =mass/Molar Mass

Molar mass of NaOH= 22.9+16+1=39.9g/mol

Substituting

m=80/39.9

=2.0moles

Volume has to be in litres

There's 1000ml to a litre

So 500ml equals 0.5litres

Molarity = 2/0.5

= 4M.