All flashcards
Flashcard 1: What is the conjugate base of acetic acid, CH₃COOH?
Answer: CH₃COO⁻. Loses a proton to form the conjugate base.
Flashcard 2: How do you find [OH−] from pOH?
Answer: [OH−]=10−pOH. Inverse logarithm converts pOH back to concentration.
Flashcard 3: How is pKb calculated from Kb?
Answer: pKb=−log(Kb). Negative logarithm converts base constant to pK scale.
Flashcard 4: Which is stronger: an acid with Ka=1.0×10−4 or Ka=1.0×10−6?
Answer: The acid with Ka=1.0×10−4 is stronger. Larger Ka value indicates greater acid dissociation.
Flashcard 5: Identify the effect of dilution on the pH of a weak acid solution.
Answer: Dilution increases pH slightly. Equilibrium shifts right, increasing ionization and pH.
Flashcard 6: What is the pH of a 0.05 M hydrochloric acid solution?
Answer: pH=1.3. Strong acid completely dissociates: pH=−log(0.05)=1.3.
Flashcard 7: Determine the pH of a solution if [H+]=1×10−3 M.
Answer: pH=3. Use pH=−log(1×10−3)=3.
Flashcard 8: What is the relationship between pH and pOH at 25oC?
Answer: pH+pOH=14. Sum of pH and pOH equals 14 at standard temperature.
Flashcard 9: Find Ka given pKa=4.76.
Answer: Ka=1.74×10−5. Use Ka=10−pKa=10−4.76=1.74×10−5.
Flashcard 10: What is the general expression for the equilibrium constant Ka of a weak acid?
Answer: Ka=[HA][H+][A−]. Shows equilibrium between weak acid and its dissociation products.
Flashcard 11: What is the expression for the percent ionization of a weak acid?
Answer: Percent ionization = \frac{[\text{H}^+]}{[\text{HA}]_0} \times 100\text{%}. Ratio of ionized acid to initial concentration times 100%.
Flashcard 12: What is the Bronsted-Lowry definition of a base?
Answer: A base is a proton acceptor. Accepts protons from acids in chemical reactions.
Flashcard 13: How is [H+] calculated from pH?
Answer: [H+]=10−pH. Inverse logarithm converts pH back to concentration.
Flashcard 14: What is the effect of temperature on the value of Kw?
Answer: Kw increases with temperature. Higher temperature increases water dissociation.
Flashcard 15: What is the pH of a neutral solution at 25oC?
Answer: pH=7. Equal concentrations of H+ and OH− at equilibrium.
Flashcard 16: What is the relationship between pKa and the strength of an acid?
Answer: Lower pKa means stronger acid. Lower pKa corresponds to larger Ka and stronger acid.
Flashcard 17: Calculate the pOH of a solution with [OH−]=2×10−3 M.
Answer: pOH=2.7. Use pOH=−log(2×10−3)=2.7.
Flashcard 18: What is the pH of a 0.01 M sulfuric acid solution assuming complete dissociation?
Answer: pH=2. Diprotic acid: [H+]=0.02 M, so pH=−log(0.02)=2.
Flashcard 19: Calculate the pH for [OH−]=4×10−5 M.
Answer: pH=9.6. Find pOH=4.4, then pH=14−4.4=9.6.
Flashcard 20: What is the expression for the equilibrium constant Kb of a weak base?
Answer: Kb=[B][BH+][OH−]. Shows equilibrium between weak base and its protonation products.
Flashcard 21: State the formula for calculating pH from [H+] concentration.
Answer: pH=−log([H+]). Negative logarithm converts concentration to pH scale.
Flashcard 22: How does pH change when a weak acid is diluted?
Answer: pH increases slightly. Dilution reduces concentration but increases degree of ionization.
Flashcard 23: What does a pH greater than 7 indicate?
Answer: The solution is basic. pH above 7 means hydroxide concentration exceeds hydronium.
Flashcard 24: What does a smaller Kb value indicate about the strength of a base?
Answer: The base is weaker. Lower Kb means less dissociation and weaker base.
Flashcard 25: Determine the pH of a 0.1 M NaOH solution.
Answer: pH=13. Strong base: [OH−]=0.1 M, so pOH=1, pH=13.
Flashcard 26: What is the formula for the autoionization of water?
Answer: 2H2O⇌H3O++OH−. Water molecules exchange protons to form ions.
Flashcard 27: What is the value of Kw at 25oC?
Answer: Kw=1.0×10−14. Ion product of water at standard temperature.
Flashcard 28: What does a larger Ka value indicate about the strength of an acid?
Answer: The acid is stronger. Higher Ka means greater dissociation and stronger acid.
Flashcard 29: Determine the pKb given Kb=4.5×10−4.
Answer: pKb=3.35. Use pKb=−log(4.5×10−4)=3.35.
Flashcard 30: Find the pKa given Ka=1.8×10−5.
Answer: pKa=4.74. Use pKa=−log(Ka)=−log(1.8×10−5)=4.74.