ACIDS, BASES, AND SALTS

Transcription

1 ACIDS, BASES, AND SALTS Chapter Quiz Choose the best answer and write its letter on the line. 1. A solution in which the hydroxide-ion concentration is is a. acidic. c. neutral. b. basic. d. none of the above 2. What is the ph of a solution in which [OH ] = ? a. 5.0 c. 5.0 b. 9.0 d If the [H + ] in a solution is mol/l, then the [OH ] is a mol/l. c mol/l. b mol/l. d. cannot be determined 4. In the reaction: the carbonate ion is acting as a(n) a. Arrhenius base. c. Brønsted-Lowry base. b. Arrhenius acid. d. Brønsted-Lowry acid. 5. Identify the Brønsted-Lowry base and conjugate base in this reaction. a. H2S and H2O c. HS and H2O b. H2S and H3O + d. HS and H3O + 6. For the reaction, the equilibrium concentrations are as follows. Ka would be: [HX] = ; [H + ], [X ] =

2 a c b d (CH3COOH/CH3COO ) buffer is a. b. c. d. 8. Which salt hydrolyzes water to form a solution that is acidic? a. LiBr c. NaBr b. NH4Br d. KBr ACIDS, BASES, AND SALTS Chapter Test A A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A 5. H3O + 1. acid dissociation constant 6. [OH ] and [H + ] = [H + ] greater than [OH ] 7. [OH ] greater than [H + ] 3. The cations or anions of a dissociated salt remove hydrogen ions from or donate hydrogen ions to water. 8. ion-product constant for water 4. point of neutralization of the titration

3 9. describes a substance that can act as both an acid and a base Column B 10. two substances that are related by the loss or gain of a single hydrogen ion a. acidic solution b. conjugate acid base pair c. amphoteric d. alkaline solution e. Kw f. end point g. neutral solution h. hydronium ion i. Ka j. salt hydrolysis B. Multiple Choice Choose the best answer and write its letter on the line. 11. A solution in which the hydroxide-ion concentration is M is a. acidic. c. neutral. b. basic. d. none of the above 12. In a neutral solution, the [H + ] is a c M.

4 b. zero. d. equal to [OH ]. 13. The products of the self-ionization of water are a. H3O7 + and H2O. c. OH + and H. b. HO and OH +. d. OH and H Which of these solutions is most basic? a. [H + ] = c. [H + ] = b. [OH ] = d. [OH ] = The formula of the hydrogen ion is often written as a. H2O +. c. H +. b. OH +. d. H3O. 16. What is the ph of a solution in which the [H + ] = ? a. 1.0 c. 2.0 b. 2.0 d What is the ph of a 0.01M hydrochloric acid solution? a c. 2.0 b d The Ka of carbonic acid is This means that H2CO3 is a a. good hydrogen-ion acceptor. b. poor hydrogen-ion acceptor c. good hydrogen-ion donor. d. poor hydrogen-ion donor. 19. Which of the following pairs consist of a weak acid and a strong base? a. ethanoic acid, sodium hydroxide b. ethanoic acid, calcium hydroxide c. sulfuric acid, sodium hydroxide d. ethanoic acid, ammonia

5 20. In the reaction, water is acting as a(n) a. Arrhenius acid. c. Brønsted-Lowry acid. b. Brønsted-Lowry base. d. Arrhenius base. 21. A solution with a ph of 5.0 a. is basic. b. has a hydrogen-ion concentration of 5.0M. c. is neutral. d. has a hydroxide-ion concentration of M. 22. With solutions of strong acids and strong bases, the word strong refers to a. molality. c. solubility. b. molarity. d. degree of ionization. 23. The hydrolysis of water by the salt of a weak base and a strong acid should produce a solution that is a. weakly basic. c. strongly basic. b. neutral. d. acidic. 24. Which of these is an Arrhenius base? a. KOH c. H2PO4 b. NH3 d. CH3COOH 25. Which of these acids is monoprotic? a. CH3COOH c. H2SO4 b. H2CO3 d. H3PO4 26. A solution that contains one mole of Ca(OH)2 and one mole of H2SO4 is a. CaSO4 + H3O + + H2O. c. CaH2 + H3SO4. b. CaSO4 + H3O + + OH. d. CaSO4 + 2H2O. 27. According to the Brønsted-Lowry theory, water a. acts as a base when it accepts a hydrogen ion. b. can be neither an acid nor a base. c. acts as an acid by accepting hydrogen ions.

6 d. can accept but not donate hydrogen ions. 28. What are the Brønsted-Lowry acids in this equilibrium reaction? a. H2O, OH c. H2O, HCN b. CN, OH d. CN, H2O 29. A solution of one of the following compounds is acidic because one of its ions undergoes hydrolysis. The compound is a. KCl. c. CH3COOK. b. NH4Cl. d. NH3. C. Problems Solve the following problems in the space provided. Show your work. 30. Calculate the ph for the following solutions. State whether each solution is acidic, basic, or neutral. a. [H + ] = b. [OH ] = c. [H + ] = Calculate the hydrogen-ion concentration [H + ] for an aqueous solution in which [OH ] is mol/l. Is this solution acidic, basic, or neutral? 32. Write the expression for Ka for each acid. Assume that only one hydrogen is ionized in each case.

7 a. H2SO3 b. HNO3 33. Write complete and balanced equations for each of the following acid base reactions. a. HBr + Mg(OH)2 b. H2SO4 + Al(OH)3 34. Predict whether an aqueous solution of each salt will be acidic, basic, or neutral. a. Na2CO3 c. (NH4)SO4 b. KNO3 d. Mg(C2H3O2)2 D. Essay Write a short essay for the following. 35. Compare and contrast the properties of acids and bases.

8 ACIDS, BASES, AND SALTS Chapter Test B A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A 1. a substance that can donate a pair of electrons to form a covalent bond 2. a compound that produces hydroxide ions when dissolved in water 3. the particle formed when a weak base gains a hydrogen ion (mol/l) 2 5. a substance that can accept a pair of electrons to form a covalent bond 6. a compound that produces hydrogen ions when dissolved in water 7. H2SO4 8. when the number of moles of hydrogen ions equals the number of moles of hydroxide ions in titration 9. describes a substance that can act as both an acid and a base 10. the process of adding a

9 known amount of solution of known concentration to determine the concentration of another solution Column B 11. reactions in which an acid and a base react in an aqueous solution to produce a salt and water a. the ion-product constant for water b. Lewis base c. acid d. conjugate acid e. neutralization reaction f. Lewis acid g. base h. diprotic acid i. amphoteric j. titration k. equivalence point B. Multiple Choice Choose the best answer and write its letter on the line. 12. Which of the following is true about acids? a. Acids give foods a bitter taste.

10 b. Aqueous solutions of acids conduct electricity. c. Acids have a ph value greater than 7. d. all of the above 13. The products of the neutralization reaction between HNO2(aq) and Ca(OH)2(aq) are a. CaNO3 + H2O. c. CaNO3 + 2H2O. b. Ca(NO3)2 + H2O. d. Ca(NO3)2 + 2H2O. 14. A solution in which the [H + ] is mol/l is said to be a. acidic. c. neutral. b. basic. d. none of the above 15. What is the ph of the solution in question 14? a c b d A solution with a ph of 9 has a [OH ] concentration of a mol/l. c mol/l. b mol/l. d mol/l. 17. Among the following, which solution is the most acidic? a. [H + ] = mol/l c. [OH ] = mol/l b. ph = 3 d. ph = The monoprotic acid from among the following is a. H2CO3. c. H3PO4. b. H2SO4. d. HCl. 19. The Brønsted-Lowry theory defines an acid as a(n) a. hydrogen ion donor. c. electron-pair donor. b. hydrogen ion acceptor. d. electron-pair acceptor. 20. Which of the following is true about neutralization reactions? a. They involve strong acids and strong bases. b. They result in the production of a salt and water.

11 c. They are all double-replacement reactions. d. all of the above 21. In the reaction: HCl(g) + NH3(aq) NH4 + (aq) + Cl (aq), HCl(g) is acting as a(n): a. Brønsted-Lowry acid. c. Lewis acid. b. Brønsted-Lowry base. d. Lewis base. 22. The conjugate acid in the reaction described in question 21 is a. HCl(g). c. NH4 + (aq). b. NH3(aq). d. Cl (aq). 23. Which of the following is true about indicators? a. They are weak acids or bases. b. They are as accurate as a ph meter. c. They maintain their colors across the range of ph values for which they are used. d. all of the above 24. What is the Lewis acid in the following reaction? NH3 + BI3 I3BNH3 a. NH3 c. I3BNH3 b. BI3 d. none of these 25. Among the following Ka values, which represents the strongest acid? a. Ka = c. Ka = b. Ka = d. Ka = How many moles of Mg(OH)2(aq) would be required to neutralize 3.0 mol HCl(aq)? a. 1.5 mol c. 6.0 mol b. 3.0 mol d. 2.0 mol C. Problems Solve the following problems in the space provided. Show your work. 27. Calculate the [OH ] for an aqueous solution in which [H + ] = mol/l. Is the solution acidic, basic, or neutral?

12 28. For each of the following, fill in the concentration of the requested ion, the ph, and the type of solution (acid, base, or neutral). a. [H + ] = [OH ] = Concentration ph Solution Type b. [OH ] = [H + ] = c. [H + ] = [OH ] [H + ] = 29. Write the expression for Ka for each of the following acids. Assume that only one hydrogen is ionized. a. HI b. H2SO4 30. Write complete and balanced equations for each of the following neutralization reactions: a. HF(aq) + KOH(aq) b. H2SO4(aq) + LiOH(aq) 31. How many moles of sulfuric acid would be required to neutralize 0.35 mol of KOH? 32. If the Ksp for a CuCl solution is , what is the concentration of Cu and of Cl ions at equilibrium? D. Essay Write a short essay for the following.

13 33. Distinguish between the Brønsted-Lowry and Lewis theories of acids and bases. E. Additional Problems Solve the following problems in the space provided. Show your work. 34. Determine the ph of a solution whose [H + ] = mol/l. Is the solution acidic, basic, or neutral? 35. Use the Brønsted-Lowry definitions of acids and bases to identify the acid, base, conjugate acid, and conjugate base in each of the following reactions. a. b. c. a. Acid Base Conjugate Acid Conjugate Base b. c. 36. Identify the Lewis acids and bases in the following reactions: Lewis Acid Lewis Base a. H + + I HI b. NH3 + BCl3 Cl3BNH3 37. A M solution of ethanoic acid (HC2H3O2) is only partially ionized so that [H ] = M. What is the acid dissociation constant for this acid?

14 ACIDS, BASES, AND SALTS Practice Problems In your notebook, solve the following problems. SECTION 19.1 ACID BASE THEORIES 1. Identify the hydrogen ion donor(s) and hydrogen ion acceptor(s) for ionization of H2SO4 in water. Label the conjugate acid-base pairs. 2. Identify all of the ions that may be formed when H3PO4 ionizes in water. 3. Classify the following acids as monoprotic, diprotic, or triprotic. a. HCOOH b. HBr c. H2SO3 d. H3ClO4 4. What would you expect to happen when lithium metal is added to water? Show the chemical reaction. 5. In the following chemical reaction, identify the Lewis acid and base. 6. Describe some distinctive properties of acids. 7. Describe some distinctive properties of bases. SECTION 19.2 HYDROGEN IONS AND ACIDITY 1. A solution has a hydrogen ion concentration of M. What is its ph? 2. What is the ph of a solution if the [H + ] = M? 3. What is the poh of a solution if the [OH ] = M? 4. What is the poh of a solution that has a ph of 3.4? 5. Classify each solution as acidic, basic, or neutral. a. [H + ] = M d. [H + ] = M b. poh = 12.0 e. ph = 0.8

15 c. [OH ] = M 6. Calculate the ph of each solution. a. [H + ] = M c. [OH ] = M b. [H + ] = M d. poh = Classify the solutions in problem 6 as acidic or basic. 8. Why is there a minus sign in the definition of ph? 9. A solution has a poh of What is the ph of this solution? 10. What is the ph of a solution with [H ] = M? SECTION 19.3 STRENGTHS OF ACIDS AND BASES 1. Rank 1M of these compounds in order of increasing hydrogen ion concentration: weak acid, strong acid, strong base, weak base. 2. Write the expression for the acid dissociation constant of the strong acid hydrofluoric acid, HF. 3. Write the expression for the base dissociation constant for hydrazine, N2H4, a weak base. Hydrazine reacts with water to form the N2H5 + ion. 4. Use Table 19.8 in your textbook to rank these acids from weakest to strongest: HOOCCOOH, HCO3, H2PO4, HCOOH. 5. Write the equilibrium equation and the acid dissociation constant for the following weak acids. a. H2S b. NH4 + c. C6H5COOH 6. Match each solution with its correct description. a. dilute, weak acid (1) 18M H2SO4(aq) b. dilute, strong base (2) 0.5M NaOH(aq) c. concentrated, strong acid (3) 15M NH3(aq) d. dilute, strong acid (4) 0.1M HC2H3O2(aq) e. concentrated, weak base (5) 0.1M HCl(aq) 7. Write the base dissociation constant expression for the weak base analine, C6H5NH2. 8. A 0.10M solution of formic acid has an equilibrium [H + ] = M. HCOOH(aq) H + (aq) + HCOO (aq)

16 What is the Ka of formic acid? 9. The Ka of benzoic acid, C6H5COOH, is What is the equilibrium [H + ] in a 0.20M solution of benzoic acid? 10. A 0.10M solution of hydrocyanic acid, HCN, has an equilibrium hydrogen ion concentration of M. What is the Ka of hydrocyanic acid? SECTION 19.4 NEUTRALIZATION REACTIONS 1. What is the molarity of a sodium hydroxide solution if 38 ml of the solution is titrated to the end point with 14 ml of 0.75M sulfuric acid? 2. If 24.6 ml of a Ca(OH)2 solution is needed to neutralize 14.2 ml of M HC2H3O2, what is the concentration of the calcium hydroxide solution? 3. A 12.4 ml solution of H2SO4 is completely neutralized by 19.8 ml of M Ca(OH)2. What is the concentration of the H2SO4 solution? 4. What volume of 0.12M Ba(OH)3 is needed to neutralize 12.2 ml of 0.25M HCl? 5. A 55.0-mg sample of Al(OH)3 is reacted with 0.200M HCl. How many milliters of the acid are needed to neutralize the Al(OH)3? SECTION 19.5 SALTS IN SOLUTION 1. A buffer solution is prepared by mixing together equal quantities of formic acid, HCHO2, and sodium formate, Na- CHO2. Write equations that show what happens when first acid, and then base, is added to this buffer solution. 2. Complete the following rules. a. strong acid + strong base c. weak acid +strong base b. strong acid + weak base