SCH 4UI – Acids and Bases
Name: ___________________________
Partners: ______________________________________
Procedure #1: Determination of the concentration of a Strong Base (KOH)
1.
2.
3.
4.
Using a pipette, add 10.00 mL of KOH to a 125 mL Erlenmeyer flask, and add 4 drops of
phenolphthalein indicator (solution should turn pink).
Fill a clean dry buret with HCl as directed. Remember to get rid of the air at the tip of the buret.
Record the initial volume of the buret.
Titrate the KOH with the HCl as instructed until the pink colour disappears. Record the initial and
final volumes of the buret.
Repeat two or three more trials until the results agree within 2%
Data
Titration of 10.00 mL of KOH with 1.00 mol/L HCl
Trial
Final burette reading (mL)
Initial burette reading (mL)
Volume of HCl(aq) used
1
2
3
4
5
6
Average
5. Obtain the average volume of your closest three trials.
6. Write out the balanced neutralization reaction that occurs in this experiment.
7. Determine the concentration of the vinegar.
 Determine the number of moles of HCl used (given the average volume of HCl used and the
concentration of the HCl) (remember C = n/V or n=CV)
 Using mole ratios, determine the number of moles of KOH neutralized.
 Determine the concentration of the KOH (C = n/V) given the number of moles of KOH and the
volume of KOH used in the Ehrlenmeyer flask)
8. Determine the [OH-] and pH of KOH
9. Show your calculations clearly in the space below
Calculations
Sources of Error
1. Suggest 3 potential sources of error in this experiment.
Procedure
1.
2.
3.
4.
Using a pipette, add 10.00 mL of HC2H3O2 (acetic acid/ethanoic acid/vinegar) to a 125 mL
Erlenmeyer flask, and add 4 drops of phenolphthalein indicator (solution should remain colourless).
Fill a clean dry buret with NaOH as directed. Remember to get rid of the air at the tip of the buret.
Record the initial volume of the buret.
Titrate the vinegar with the NaOH as instructed until the pink colour appears. Record the initial
and final volumes of the buret.
Repeat two or three more trials until the results agree within 2%
Data
Titration of 10.00 mL of HC2H3O2 with 1.00 mol/L NaOH
Trial
Final burette reading (mL)
Initial burette reading (mL)
Volume of NaOH(aq) used
1
2
3
4
5
6
Average
5. Obtain the average volume of your closest three trials.
6. Write out the balanced neutralization reaction that occurs in this experiment.
7. Determine the concentration of the vinegar.
 Determine the number of moles of NaOH used (given the average volume of NaOH used and
the concentration of the NaOH) (remember C = n/V or n=CV)
 Using mole ratios, determine the number of moles of vinegar (acetic acid/ethanoic acid)
neutralized.
 Determine the concentration of the vinegar (C = n/V) given the number of moles of vinegar and
the volume of vinegar used in the Ehrlenmeyer flask)
8. Determine the [H+] and pH of HC2H3O2(aq) (Ka for HC2H3O2(aq) = 1.8 x 10-5)
9. Show your calculations clearly in the space below
Calculations
Sources of Error
1. Suggest 3 potential sources of error in this experiment.