General A/B Workseet . Answersat the bottom

1. How do you describe Arrhenius acids and bases?

2. Classify each as an Arrhenius acid or Arrhenius base

Ca(OH)2 –

HNO3 –

KOH –

C2H5COOH –

HBr –

H2SO4 –

3. Write the reaction for the dissociation of each compound in water

Potassium hydroxide

Magnesium hydroxide

4. Identify each reactant as a hydrogen ion donater or a hydrogen ion acceptor

HNO3 + H2OH3O+ + NO3-

CH3COOH + H2O H3O+ + CH3COO-

NH3 + H2O NH4+ + OH-

H2O + CH3COO- CH3COOH + OH-

5. Label the conjugate-acid pairs in each equation in Problem 47

6.What are the concentrations of H+ and OH- in pure water at 25 degrees celcius?

7. How is the pH solution calculated?

8. Why is the pH of pure water at 25 C equal to 7.00?

9. Calculate the pH for the following solutions and indicate whether each solution is acidic or basic.

  1. [H+] = 1 X 10-2 M
  2. [OH-] = 1 X 10-2 M
  3. [OH-] = 1 X 10-8 M

10. What are the hydroxide-ion concentrations for the following pH values?

  1. 4.00b. 8.00c. 12.00

11. Use the Bronsted-Lowry definitions of acids and bases to identify each as an acid or a base.

  1. KOH + HBr <—> KBr + H20
  2. HCl + H2O <—> Cl- + H3O+

12. Calculate the [OH-] or pH of each solution

  1. pH = 4.60
  2. pH = 9.30
  3. [OH-] = 1.8 X 10-2 M
  4. [OH-] = 7.3 X 10-9 M

13. Identify the products and write balanced equations for each neutralization reaction.

  1. HNO3 (aq) + KOH (aq) —>
  2. HCl (aq) + Ca(OH)2 (aq) —>
  3. H2SO4 (aq) + NaOH (aq) —>

14. What is characteristic of the end point of a titration?

15. What is the molarity of sodium hydroxide if 20.0 mL of the solution is neutralized by each of the following 1.00 M solutions?

  1. 28.0 mL of HCl
  2. 17.4 mL of H3PO4

16. What kinds of salts hydrolyze water?

17. Write an equation showing why sodium hydrogen carbonates is basic.

18. Predict whether an aqueous solution of each salt will be acidic, basic, or neutral.

a. Na2CO3

  1. KCl
  2. Na2SO4
  3. NH4NO3
  4. Na2CO3
  5. NH4Cl

19. A buffered solution cannot absorb an unlimited amount of acid or base. Explain.

Answers

1. How do you describe Arrhenius acids and bases?

Acids ionize to give hydrogen ions in aqueous solution. Bases DISOCCIATE to give hydroxide ions in aqueous solution.

2. Classify each as an Arrhenius acid or Arrhenius base

Ca(OH)2 – Base

HNO3 – Acid

KOH – Base

C2H5COOH – Acid

HBr – Acid

H2SO4 – Acid

3. Write the reaction for the dissociation of each compound in water

Potassium hydroxide KOHK+ + OH-

Magnesium hydroxide Mg(OH)2Mg2+ + 2OH-

4. Identify each reactant in the equations as a hydrogen ion donater or a hydrogen ion acceptor

HNO3 + H2OH3O+ + NO3- HNO3 is acid, H2O is base

CH3COOH + H2O H3O+ + CH3COO- CH3COOH is the acid, H2O is the base

NH3 + H2O NH4+ + OH- H2O is the acid, NH3 is the base

H2O + CH3COO- CH3COOH + OH- H2O is the acid, CH3COO- is the base

5. Label the conjugate-acid pairs in each equation in Problem 47

Nitric acid with nitrate, water with hydronium

Acetic acid wit acetate, water with hydronium

Water with hydroxide, ammonia with ammonium

Water with hydroxide, acetate with acetic acid

6.What are the concentrations of H+ and OH- in pure water at 25 degrees celcius?

1.0x 10-7 M for both H+ and OH-

7. How is the pH solution calculated?

The - logarithm of the [H+]

8. Why is the pH of pure water at 25 C equal to 7.00?

The hydrogen concentration of pure water is the square root of 1.0x10-14, or 10 x 10-7M. The negative logarithm or pH of this concentration is 7.0

9. Calculate the pH for the following solutions and indicate whether each solution is acidic or basic.

  1. [H+] = 1 X 10-2 M
  2. [OH-] = 1 X 10-2 M
  3. [OH-] = 1 X 10-8 M

a. pH = 2.00, acidic b. pH = 12.00, basic c. pH = 6.00, acidic

10. What are the hydroxide-ion concentrations for solutions with the following pH values?

  1. 4.00b. 8.00c. 12.00

a. 1.0 X 10-10 M b. 1.0 X 10-6 M c. 1.0 X 10-2 M

11. Use the Bronsted-Lowry definitions of acids and bases to identify each as an acid or a base.

  1. KOH + HBr <—> KBr + H20
  2. HCl + H2O <—> Cl- + H3O+

KOH-base, HBr-acid HCl-acid, H2O-base

12. Calculate the [OH-] or pH of each solution

  1. pH = 4.60
  2. pH = 9.30
  3. [OH-] = 1.8 X 10-2 M
  4. [OH-] = 7.3 X 10-9 M

a. [OH] = 4.0 X 10-10 ‘

b. [OH-] = 2.0 X 10-5

c. 12.26

d. 5.8

13. Identify the products and write balanced equations for each neutralization reaction.

  1. HNO3 (aq) + KOH (aq) —> KNO3 + H2O
  2. HCl (aq) + Ca(OH)2 (aq) —> CaCl2 + 2H2O
  3. H2SO4 (aq) + NaOH (aq) —> Na2SO4 + 2H2O

14. What is characteristic of the end point of a titration?

The indicator changes color

15. What is the molarity of sodium hydroxide if 20.0 mL of the solution is neutralized by each of the following 1.00 M solutions?

  1. 28.0 mL of HCl
  2. 17.4 mL of H3PO4
  1. 1.40 M
  2. 2.61 M

16. What kinds of salts hydrolyze water?

Salts with a cation from a weak base and an anion from a strong acid, or with a cation from a strong base and an anion form a weak acid.

17. Write an equation showing why sodium hydrogen carbonates is basic.

HCO3-(aq) + H2O(l)  H2CO3(aq) + OH-(aq)

Predict whether an aqueous solution of each salt will be acidic, basic, or neutral.

a. Na2CO3

  1. KCl
  2. Na2SO4
  3. NH4NO3
  4. Na2CO3
  5. NH4Cl

a. basic b. acidic c. neutral d. basic e. neutral

70. A buffered solution cannot absorb an unlimited amount of acid or base. Explain.

Eventually the buffer capacity of the buffer is exceeded and the pH will change significantly with the addition of a strong acid or base.