Question

calculate the molarity of the following solutions.

0.150mol of Na2S in 1.45L Solution

26.7g of MgS in 995ml of solution

Answer 1

Answer – Given, 0.150 mol of Na₂S , volume of solution = 1.45 L

We know molarity formula

Molarity = moles / volume (L)

               = 0.150 mol / 1.45 L

               = 0.103 M

Given, mass of MgS = 26.7 g , volume = 995 mL

First we need to calculate moles of 26.7 g of MgS

We know

Moles = mass / molar mass

           = 26.7 g / 56.37 g.mol^-1

           = 0.474 moles

So, molarity = moles / volume (L)

                     = 0.474 moles / 0.995 L

                     = 0.476 M