Chemistry Questions and Answers February 17, 2020

The acetic acid (HOAC) content of vinegar is determined by titrating with a standard solution of sodium hydroxide to a phenolphthalein end point. (a) A 1 mL pipet carries an uncertainty of 0.02 mL, while a 10 mL pipet has an uncertainty of 0.08 mL. Which one do you prefer in order to transfer 10 mL vinegar sample to a volumetric flask (b) The

Some amino acids give unique properties to proteins that can be exploited bioanalytically (i.e., reactive side chains). List the amino acids that fall into this category and for each amino acid on the list, indicate the properties that make that amino acid unique and how these properties can be exploited.

Suppose 30 g of Benzoyl peroxide is introduced to 5 kg of polypropylene monomer. If 20% of the initiator groups are effective, calculate the expected degree of polymerization and the molecular weight of the polymer if a) all the termination reaction occurs by combination and b) all the termination occurs by disproportionation.

The acid-catalyzed hydrolysis of sucrose occurs by the following overall reaction whose kinetic data are given below: C 12 H 2 O 11 (s) +H 2 O (l) C 6 H 12 O 6 (aq) +C 6 H 12 O 6(aq) sucrose glucose fructose (a) Determine the rate constant and the half-life of the reaction. (b) How long does it take to hydrolyze 75% of the sucrose? (c) Other

Sucrose (molL) Time (h) 0.501 0.00 0.451 0.50 0.404 1.00 0.363 1.50 0.267 3.00

The amount of Fe in a 0.4891g sample of an ore was determined by titrating with KCrO. After dissolving the sample in HCI, the iron was brought into the 2 oxidation state using a Jones reductor. Titration to the diphenylamine sulfonic acid end point required 36.92 mL of 0.02153 M KCrO. Report the ores iron content as ww FeO. Cr0, 14H 6e 2Cr