Ch.10 Acids and Bases
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- Write a balanced equation for the proton transfer reaction between hydrofluoric acid (HF) and ammonia (NH₃). Identify each conjugate acid-base pair, and rewrite the equilibrium arrows to indicate if the forward or reverse reaction is favored.
Problem 8
- From this electrostatic potential map of the amino acid alanine, identify the most acidic hydrogens in the molecule:
Problem 9
- Show how ethylamine (C₂H₅NH₂) reacts with hydrochloric acid to form an ethylammonium salt.
Problem 23
- One of these pictures represents a solution of HCl and one represents a solution of H 2 SO 4 . Which is which? a.
Problem 28
b.
- Electrostatic potential maps of acetic acid (CH₃CO₂H) and ethyl alcohol (CH₃CH₂OH) are shown. Identify the most acidic hydrogen in each, and tell which of the two is likely to be the stronger acid.
Problem 34
- What happens when a strong acid such as HBr is dissolved in water?
Problem 38
- What happens when a weak acid such as CH₃CO₂H is dissolved in water?
Problem 39
- What happens when a strong base such as KOH is dissolved in water?
Problem 40
- What happens when a weak base such as NH₃ is dissolved in water?
Problem 41
- What is the difference between a monoprotic acid and a diprotic acid? Give an example of each.
Problem 42
- What is the difference between H⁺ and H₃O⁺?
Problem 43
- How is K_w defined, and what is its numerical value at 25 °C?
Problem 51
- Rearrange the equation you wrote in Problem 10.50 to solve for [H₃O⁺] in terms of Kₐ.
Problem 71
- What is the difference between an acid and a base?
Problem 74
- Write equations to show how the substances listed in Problem 3.75 give ions when dissolved in water.
Problem 76
- The pH of a buffer solution containing 0.10 M acetic acid and 0.10 M sodium acetate is 4.74. Write the Henderson–Hasselbalch equation for this buffer.
Problem 76
- How does normality compare to molarity for monoprotic and polyprotic acids?
Problem 83
- Identify the number of equivalents per mole for each of the following acids and bases. H₃PO₄
Problem 84
- How many equivalents of an acid or base are in the following? 0.25 mol Mg(OH)₂
Problem 88
- What are the molarity and the normality of a solution made by dissolving 5.0 g of Ca(OH)₂ in enough water to make 500.0 mL of solution?
Problem 90
- What are the molarity and the normality of a solution made by dissolving 25 g of citric acid (triprotic,C₆H₅O₇H₃) in enough water to make 800 mL of solution?
Problem 91
- The dissociation of water into H₃O⁺ and OH⁻ ions depends on temperature. At 0 °C the [H₃O⁺] = 3.38 x 10⁻⁸ M, at 25 °C the [H₃O⁺] = 1.00 x 10⁻⁷ M, and at 50 °C the [H₃O⁺] = 2.34 x 10⁻⁷ M. What is the value of K_w at 0 °C and 50 °C.
Problem 99
- The dissociation of water into H₃O⁺ and OH⁻ ions depends on temperature. At 0 °C the [H₃O⁺] = 3.38 x 10⁻⁸ M, at 25 °C the [H₃O⁺] = 1.00 x 10⁻⁷ M, and at 50 °C the [H₃O⁺] = 2.34 x 10⁻⁷ M. Is the dissociation of water endothermic or exothermic?
Problem 99
- One of the buffer systems used to control the pH of blood involves the equilibrium between H₂PO₄⁻ and H₂PO₄²⁻. The pKₐ for H₂PO₄²⁻ is 7.21. Write the Henderson–Hasselbalch equation for this buffer system.
Problem 103
- Obtain a package of Alka-Seltzer, an antacid, from the local drug store: Why does Alka-Seltzer foam and bubble when dissolved in water? Which ingredient is the antacid?
Problem 109
- Research the composition of 'smelling salts'—a product that is used to rouse people who have lost consciousness. What are the chemical reactions that generate the 'active' component?
Problem 110
- Many allergy medications contain antihistamines, compounds that contain amine groups (R-NH₂, where R refers to an organic functional group). Would you expect these compounds to be acidic, basic or neutral? Explain. One over-the-counter product lists the active ingredient as 'diphenhydramine HCl.' What does this designation mean?
Problem 111
