POSTLAB QUESTIONS

SHOW SET-UP FOR ALL PROBLEMS

1. What are the products of any acid-base neutralization?

2. A base solution is standardized with KHP. The KHP is titrated to a dark pink phenolphthalein endpoint (rather than a light pink endpoint). How is the calculated concentration of base affected?

3. Use the following tabulated data to determine the average molar mass of an unknown acidic solid. The acid and base react in a 1:1 mole ratio.

	Trial #1	Trial #2	Trial #3
mass of unknown acid	0.532 g	0.498 g	0.552 g
(0.2500M base in buret)
initial buret reading	0.42 mL	1.55 mL	1.12 mL
final buret reading	28.63 mL	28.07 mL	30.29 mL

4. A student took her initial buret reading (with the funnel still in the top of the buret). During the titration, a drop of liquid fell off the funnel and into the buret. The student reaches the endpoint of the titration and takes the final buret reading. How does the calculated liquid volume differ from the true volume of liquid used in the titration? (too high, too low, the same) Explain.