Question

9. Weigh two samples of KHP in the 125 mL Erlenmeyer flask directly, weighing out enough to react with ~25 mL of 0.1M NaOH solution. How much KHP is enough?

10. When you are ready to titrate the solution, dissolve the KHP with 25 mL DI water.

Answer 1

KPH + NaOH ↔ NaKP + H2O

First, we need to know the number of moles of NaOH we have. We have 25 mL of a 0.10 M solution of NaOH. M=moles/liter, so we have 25 mL of a 0.10 mole/liter solution.

If we convert mL to liters, we get 25 mL x 1 L/1000 mL = 0.025 L

We multiply the number of liters by the moles/liter to get the number of moles:

0.025 L x 0.10 moles/L - 0.0025 moles NaOH

Since we know from our reaction equation above that we need 1 mole of KPH for each mole of NaOH, we know we need 0.0025 moles KPH.

Now we need to convert moles of KPH to grams KPH. The molecular mass of KPH is 204 g/mol.

To get the number of grams, we need to multiply the number of moles by the molecular mass:

0.0025 moles KPH * 204g/mol = 0.51 g KPH.