 | Sample Lab Questions Investigation #12:
"Formula Weight of a Fatty Acid"
|
These questions have been taken from lab quizzes given in previous years.
Some of the answers are listed at the end.
Note: The subscripts and superscripts may not appear as such. It depends upon your web browser.
- 1.
- (2pts) Define "primary standard" and give an example of one that you used in laboratory this semester.
- 2.
- a. (1pt) Explain why the sodium hydroxide solution must be standardized.
- b. (1pt) What chemical compound did you use to standardize the NaOH solution?
- 3.
- (2pts) Given the general formula of a fatty acid: CnH2n+1CO2H, and the molecular mass of your fatty acid, how do you calculate "n" to determine the formula of your fatty acid?
- 4.
- (1pt) Define "acid."
- 5.
- (2pts) How many grams of solid sodium hydroxide will be needed to prepare 250 mL of 1.5 M NaOH solution?
- 6.
- a. (2pts) If 28.56mL of a NaOH solution neutralized 0.6223g of KHP (C8H5O4K), what is the molarity of the NaOH solution?
- b. (1pt) If 28.46 mL of this NaOH solution was used to neutralize a 0.6923 g fatty acid sample, what is the molecular mass of the fatty acid?
- c. (2pts) Determine the molecular formula of the fatty acid.
Answers
| 6. | a. | 0.1067 M NaOH |
| b. | 228.0 g fatty acid/mol |
| c. | n = 13, so C13H27CO2H or CH3(CH2)12CO2H |
To report any corrections, please e-mail Dr. Wendy Keeney-Kennicutt.