Laboratory assignment for module 5: standardization of a solution

Laboratory Assignment for Module 5: Standardization of a Solution
(eScience Lab 7 [19])

Mass of beaker:

Mass of beaker and citric acid:

Mass of beaker and citric acid (after cooling):

Volume of NaOH:

Table 1. Trial 1 Data

Table 2. Trial 2 Data

III. CALCULATIONS (15 POINTS)

Include your graphs with your report.

Mass of citric acid:

Moles of citric acid:

(MW = 192.0 g/mol)

Molarity of citric acid:

(volume of solution = 100 mL)

Trial 1 equivalence point:

Trial 2 equivalence point:

Show calculations

IV.  RESULTS (20 POINTS)

Molarity (Trial 1):

Molarity (Trial 2):

Average Molarity:

1.      Use Figure 3 in your laboratory manual to determine which combination of acids and bases provide the most distinguishable equivalence point. Which combination is the most difficult to determine an equivalence point? (10 points)

2.      There are many different primary standards that could be used in a standardization titration. What are the criteria of a primary standard?(10 points)

3.      Potassium hydrogen phthalate (KHP; KHC₈H₄O₄) is a good primary standard. If it took 20.0 mL of NaOH to react with 15.5 mL of 0.600 M KHP solution, what is the molarity of the NaOH solution? (10 points)

KHC₈H₄O₄  +  NaOH  →  KNaC₈H₄O₄  +  H₂O