Question

how many moles of NH3 are in 0.250 L of a 5.00 M aqueous solution?

Answer 1

Data Given:
                   Molarity  =  5.0 mol/L

                   Volume  =  0.250 L

Solution:
             As we know a concentration unit, Molarity is the number of moles dissolved per unit volume of solution...

                        Molarity  =  Moles / Volume of Solution

As, we are in need of moles, so solve above equation for moles, i.e.

                        Moles  =  Molarity × Volume

Putting Values,

                        Moles  =  5 mol.L⁻¹ × 0.250 L

                        Moles  =  1.25 Moles