Question

What is the molarity of a solution containing 13.7 grams of NH3 in 1.55 liters of solution?

Answer 1

Molarity = moles of solute
                 liter of solution

Step 1: calculation of moles of NH₃ in the solution

      mass of 1 mole of ammonia = 17 g/mol

      so, 13.7g of ammonia = 13.7g NH₃X 1 mole NH₃
                17g NH₃

                                               = 0.806 mol

step 2: calculation of molarity

         volume of solution = 1.55 litres

        moles of solute i.e. NH₃ = 0.806 mol

       molarity = 0.806 mol/ 1.55 L

                   = 0.52 mol/L = 0.52 Molar