How many moles of potassium chloride, kcl, are needed to make 100.0 ml of a 2.0 m kcl solution?

              0.20 Moles

Solution:

Data Given:

                  Molarity  =  2.0 mol.L⁻¹

                  M.Mass  =  74.55 g.mol⁻¹

                  Volume  =  100 mL  =  0.1 L

Formula Use:

                            Molarity  =  Moles ÷ Volume

Solving for Moles,

                            Moles  =  Molarity × Volume

Putting values,

                            Moles  =  2.0 mol.L⁻¹ × 0.1 L

                            Moles =  0.20 mol

Preparation of 2 M KCl Solution:

                                      Take 0.2 moles of KCl and pour it into a 100 mL empty volumetric flask. After that add distilled water upto the mark of 100 mL. The concentration of resulting solution will be 2.0 M.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.