Read the appropriate section of the lab introduction and procedure before starting each section.
Part A - Data Table
|
|
KHP Sample 1
|
KHP Sample 2
|
KHP Sample 3
|
|
Mass of flask and KHP (B)
|
|
|
|
|
Mass of empty flask (A)
|
|
|
|
|
Mass of KHP (B - A)
|
|
|
|
|
Final buret reading (D)
|
|
|
|
|
Initial buret reading (C)
|
|
|
|
|
Volume of base used (D - C)
|
|
|
|
Part B - Calculations. Show all of the calculation setups for each question in the space provided beneath the question. You must show your work!
1. Calculate the moles of acid in each flask:
KHP Sample 1:
KHP Sample 2:
KHP Sample 3:
2. Calculate the moles of base used for each sample (convert the moles of acid into moles of base using the balanced chemical equation):
Titration 1:
Titration 2:
Titration 3:
3. Using the moles of base determined above, and the volume of the base solution you dispensed from the buret, calculate the molarity of the base solution for each sample:
Titration 1:
Titration 2:
Titration 3:
4. Calculate the average molarity of the base solution you used in the titrations:
Instructor Initials: ______
Part C - Questions. Answer the following questions using complete sentences. For any questions requiring a calculation show the calculation setups and place a box around your final answer.
1. If you added 40 mL of water to a sample of KHP instead of 30 mL, would the titration of that sample then have required more, less, or the same amount of base? Explain.
2. A student weighs out 2.045 g of KHP. How many moles of KHP are in this sample?
3. A titration required 23.8 mL of a 0.15 M NaOH solution. How many moles of NaOH were in this volume?
4. A student weighed a sample of KHP and found it weighed 0.9803 g. The titration of this KHP required 23.45 mL of base (NaOH). Calculate the molarity of the base.