South CHM1020 Week 9 Lab Assignment

CHM120 General Chemistry I Lab

Week 9 LAB Assignment

Lab 9 Assignment

Review of acids/bases and acid-base neutralization: https://www.youtube.com/watch?v=n9wUdgxCLMQ

1.            What species is the conjugate acid of HCO3–?

2.            Which species is the conjugate base of HPO42–?

Refresher of Acid/Base Equilibria, Ka, and pKa, and buffer solutions: https://www.youtube.com/watch?v=jdmHjFp_35I

1.            The [H3O+] in a cabernet sauvignon wine is 5.9 × 10–4 M. What is the [–OH] in this wine?

2.            The pH of a lime is 1.90. What is the [H3O+]?

3.            What is the pH of a cleaning solution with a [H3O+] = 7.4 × 10–9 M H3O+?

4.            Normal gastric juice has a pH of about 2. Assuming that normal gastric juice is primarily aqueous HCl, what is the concentration of HCl in the stomach?

5.            The Ka of acetic acid is 1.7 × 10-5.  What is the pKa of acetic acid?

6.            The of formic acid is pKa 3.750.  What is the Ka of formic acid?

Titrations: Setting up and performing a titration:  https://www.youtube.com/watch?v=sFpFCPTDv2w&t=48s

Titration calculation demonstration: https://www.youtube.com/watch?v=2z4mlE6MK0U

1.            What is the molarity of an HCl solution if 43.6 mL of a 0.125 M KOH solution are needed to titrate a 25.0 mL sample of the acid according to the equation below?

2.            How many milliliters of 0.653 M NaOH are needed to neutralize 25.0 mL of a 1.02 M HBr solution? The neutralization reaction is:

3.            Each day, the stomach produces 2.0 L of gastric juice that contains 0.10 M HCl. Phillips Milk of Magnesia is a white-colored, aqueous, mildly alkaline suspension of magnesium hydroxide formulated at 8.0 % (w/v). It would take ________ mL of milk of magnesia to titrate the stomach acid produced in each day. (Mg(OH)2 molar mass = 58.32 g/mol)

Buffers: Demonstration of buffered versus unbuffered solution: https://www.youtube.com/watch?v=P-R-Cqvb5yo

1.            What is the pH of a buffer that contains 0.15 M CH3COOH and 0.10 M NaCH3COO(Ka = 1.8 × 10–5)?