Chapter 20 PMT flashcards

• What is the definition of a Bronsted-Lowry acid?

  Proton donor
• What is the definition of a Bronsted-Lowry base?

  Proton acceptor
• What is the definition of a Lewis acid?

  Electron pair acceptor
• What is the definition of a Lewis base?

  Electron pair donor
• What ion causes a solution to become acidic?

  H+ (hydrogen ion) or H3O+ (hydronium ion)
• What ion causes a solution to become alkaline?

  OH- (hydroxide ion)
• Write the equation for the ionisation of water.

  2H2O (l) ⇌ H3O+ (aq) + OH- (aq)
• Give an example of a monobasic acid.

  HCl
• Give an example of a dibasic acid.

  H2SO4
• Give an example of a tribasic acid.

  H3PO4
• Identify the acid-base pairs in the reaction: CH3COOH + H2O ⇌ CH3COO- + H3O+

  Acid 1: CH3COOH, Base 2: H2O, Base 1: CH3COO-, Acid 2: H3O+
• What is the definition of a strong acid?

  Acids that dissociate completely
• Give some examples of strong acids.

  Hydrochloric acid, Sulfuric acid, Nitric acid

  
• What is the difference between concentrated and strong?

  Concentrated means many mol per dm3, strong refers to amount of dissociation
• What is the definition of a weak acid?

  Acids that only partially dissociate
• Give some examples of weak acids.

  Methanoic acid, any organic acid
• What is the constant used to measure the extent of acid dissociation called?

  Acid dissociation constant

  
• What is the symbol of the acid dissociation constant?

  Ka

  
• What does a larger Ka value mean?

  Greater the extent of dissociation
• Write the equation used to convert Ka into pKa.

  pKa = -log10Ka
• Write the equation used to convert pKa into Ka.

  Ka = 10^-pKa
• What is the relationship between pKa and the strength of the acid?

  Smaller the pKa, stronger the acid
• Write the equation used to convert the concentration of H+ into pH.

  pH = -log[H+]
• Write the equation used to convert pH into concentration of H+.

  [H+] = 10^-pH
• What are the key differences between strong and weak acids?

  • Strong acids dissociate completely in solution
  • Weak acids only partially dissociate in solution
  • Strong acids have a higher Ka value
  • Weak acids have a lower Ka value

  
• What are the key differences between concentrated and strong acids?

  • Concentrated refers to the number of moles of acid per dm3 of solution
  • Strong refers to the extent of dissociation of the acid in solution
  • A concentrated acid can be either strong or weak
  • A strong acid can be either concentrated or dilute

  
• What are the key properties of a buffer solution?

  • Resists changes in pH when small amounts of acid or base are added
  • Contains a weak acid and its conjugate base (or a weak base and its conjugate acid)
  • Maintains a relatively constant pH
  • Used in various biological and chemical processes
• What are the key steps in calculating pH from Ka?

  1. Write the expression for Ka
  2. Set up an ICE table (Initial, Change, Equilibrium)
  3. Substitute equilibrium concentrations into the Ka expression
  4. Solve for [H+]
  5. Calculate pH using pH = -log[H+]
• What are the key steps in calculating Ka from pH?

  1. Calculate [H+] using [H+] = 10^-pH
  2. Write the expression for Ka
  3. Set up an ICE table (Initial, Change, Equilibrium)
  4. Substitute equilibrium concentrations into the Ka expression
  5. Solve for Ka
• What are the key steps in calculating pKa from Ka?

  1. Take the negative logarithm of Ka
  2. pKa = -log10Ka
• What are the key steps in calculating Ka from pKa?

  1. Take the antilog of -pKa
  2. Ka = 10^-pKa
• What are the key steps in calculating pH from [H+]?

  1. Take the negative logarithm of [H+]
  2. pH = -log[H+]
• What are the key steps in calculating [H+] from pH?

  1. Take the antilog of -pH
  2. [H+] = 10^-pH
• What are the key steps in calculating the pH of a strong acid?

  1. Assume complete dissociation of the strong acid
  2. [H+] = concentration of the strong acid
  3. Calculate pH using pH = -log[H+]
• What are the key steps in calculating the pH of a weak acid?

  1. Write the expression for Ka
  2. Set up an ICE table (Initial, Change, Equilibrium)
  3. Substitute equilibrium concentrations into the Ka expression
  4. Solve for [H+]
  5. Calculate pH using pH = -log[H+]
• What are the key steps in calculating the pH of a buffer solution?

  1. Write the expression for Ka
  2. Set up an ICE table (Initial, Change, Equilibrium)
  3. Substitute equilibrium concentrations into the Ka expression
  4. Solve for [H+]
  5. Calculate pH using pH = -log[H+]
• What are the key steps in calculating the pH of a basic solution?

  1. Calculate [OH-] using the concentration of the base
  2. Calculate pOH using pOH = -log[OH-]
  3. Calculate pH using pH = 14 - pOH
• What are the key steps in calculating the pH of a neutral solution?

  1. [H+] = [OH-] = 1 x 10^-7 M
  2. pH = 7
• What are the key steps in calculating the pH of a solution with a known [H+]?

  1. Take the negative logarithm of [H+]
  2. pH = -log[H+]
• What are the key steps in calculating the pH of a solution with a known [OH-]?

  1. Calculate pOH using pOH = -log[OH-]
  2. Calculate pH using pH = 14 - pOH