You are given 250.0 mL of a solution of potassium hydroxide that has been determ

Question

You are given 250.0 mL of a solution of potassium hydroxide that has been determined to be 0.015 molarity. This sample is placed in a 2.000 L volumetric flask and an additional 8.00g of solid potassium hydroxide are added and properly dissolved as the final volume of the solution is brought up to the mark on the flask. What is the molarity of this final solution? Doing a bit of research, can you find the numerical values that you need in order to convert this molarity into the molality of this solution? If so determine the molality of this final solution

Explanation / Answer

Number of moles of KOH = 8.00g / molar mass

= 8.00/56.1056 g/mol

=0.143 moles

Number of moles of KOH in 250 ml or 0.250 L

= Molarity * volume

= 0.015 M* 0.250L

= 0.00375 moles

Total number of moles of KOH = 0.143 moles + 0.00375 moles

=0.14675 Moles

Molarity = number of moles / volume in L

= 0.14675 Moles /2.00 L

= 0.0734 M

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