# Acid Base Calculations Homework

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```					Acids and Bases Calculations and Problems Homework: Davis              Name: _____________________________________

Remember that you will have to show all work on the test to receive credit for the math problems. You should
practice showing all work now. Do not forget your significant digits and units! (2 decimal places for pH)

Calculating Dissociation Constants
1. Acetic acid is a weak monoprotic acid. If the initial concentration of acetic acid is .200 M and the equilibrium
concentration of H3O+ is .0019 M, calculate Ka.
2. Trimethylamine is a weak base. If the initial concentration or trimethylamine is .390 M and the equilibrium
concentration of OH- is
4.4*10-3 M, calculate Kb for trimethylamine.
3. Uric acid is a weak acid. If the initial concentration of uric acid is .110 M and the equilibrium concentration of H3O+ is
3.4*10-2 M, calculate Ka for uric acid.
4. Ammonia is a weak base. If the initial concentration of ammonia is .150 M and the equilibrium concentration of OH-
is 1.6*10-3 M, calculate Kb for ammonia.

The Self Ionization of Water
5. What is the concentration of OH- ions in .1 M borax if [H3O+] = 6.31*10-10 M?
6. What is the concentration of H3O+ ions in eggs if [OH-] = 6.0*10-7 M?
7. What is the concentration of OH- ions in butter if [H3O+] = 6.0*10-7 M? Is butter acidic or basic?
8. What is the concentration of H3O+ ions in peaches if [OH-] = 3.16*10-11 M? Are peaches acidic or basic?

The pH Scale
9. In a sample of bananas and water the concentration of hydronium ion equals 2.51*10-5M. What it the pH?
10. Tomatoes have a hydronium ion concentration of 6.2*10-5 M. What is the pH? Are they acidic or basic?
11. What is the pH of pickles if the [OH-] = 1.6*10-10 M?
12. What is the pH of urine if the [OH-] 6.3*10-10? Is urine acidic, basic, or neutral?
13. What is the concentration of hydronium ions in an aqueous solution with a pH of 7.6?
14. What is the concentration of hydroxide ions in an aqueous solution with a pH of 10.3?

Buffers
15. If a solution is buffered with ammonia and ammonium, write the chemical equation for the neutralization of an acid.
16. If a solution is buffered with acetic acid and acetate, write the chemical equation for the neutralization of a base.
17. A solution is buffered with carbonic acid and bicarbonate, write the chemical equation for neutralization of an acid.
18. Determine the pH of a solution that has been buffered with .89 M NH3 and .42 M NH4Cl. Kb of ammonia is .000018
19. Determine the concentration of acetic acid and sodium acetate that you should use to buffer a solution to a pH of
4.00. The Ka of the acid is .00018.
20. Determine the pH of the solution of the previous problem if .20 mol of gaseous HCl was added to one liter of the
solution. (omit for 2011)

Titrations
21. 30.0 mL of HCl is needed to titrate a 50.0 mL sample of KOH. What is the concentration of KOH?
22. 89.2 mL of .75 M NH3 is required to titrate 25.0 mL of HCl. What is the concentration of HCl?
23. 28.6 mL .250 M NaOH is required to titrate 40.0 mL of H3PO4. What is the concentration of phosphoric acid?
24. 27.2 mL of .125 M Ca(OH)2 is required to titrate 15.0 mL of HCl. What is the concentration of HCl?
25. 82.3 mL of .0100 M H2SO4 is required to titrate 10.0 mL of Al(OH)3. What is the concentration of Al(OH)3?
26. .025 M NaOH is used to titrate 20.0 mL of .125 M HCl. What volume of NaOH will be used?
27. .500 M Ca(OH)2 is used to titrate 20.0 mL of .250 M H3PO4. What volume of calcium hydroxide will be used?

Using Ka to determine pH or ion concentrations
28. An acid, HA, has a Ka of 1.2*10-7. What is the pH of a .125 M solution of that acid?
29. A base, B, has a Kb of 1.3*10-5. What is the pH of a .525 M solution of the base?

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