Question

Mass percent KHP using and indicator.

Please show your work in chemical units, with known and unknown.

Show how you would determine the molarity of a NaOH using the titration of the NaOH with a known mass of KHP as a primary standard. Then determine the mass percent of an unknown sample of KHP. Please show how your calculation for your mass of the unknown KHP sample, average mass percent KHP and molarity of the NaOH. You may have as many theoretical samples as you wish.

You begin with:

-G known KHP and ml unknown NaOh used for the standardization of Naoh

and

- G of unknown KHP and ml unknown NaOh used for the unknown KHP

Answer 1

First calculate moles of KHP consumed in titration.

No of Moles = Mass in Grams\Molar mass

suppose xg is consumed therefore

No. of moles = (x\204.22) = y moles (suppose)

Second determine volume of NaOH consumed

This can be determined from burret reading (or may be give in questions).

Suppose AmL of NaOH is consumed. It means AmL of NaOH solution contains y moles of NaOH.

Third calculate molarity of NaOH:

Molarity = no. of moles in one liter of solution.

We have already calculated no. of moles of NaOH in AmL. Therefore we can calculate Molarity of NaOH (No. of moles of NaOH in 1000mL or 1L) by following equation:

Molarity = y\A X 1000

Determine mass of unknown sample of KHP.

Simply titrate the unknown sample of KHP with NaOH. Calculate moles of NaOH consumed. Suppose x moles of NaOH are consumed. It means there are x moles of of KHP in unknown sample.

Mass Of KHP = Molar mass X No. of moles (x)

= 204.22 X x