All flashcards
Flashcard 1: What is Kw at 25∘C for water?
Answer: Kw=[H+][OH−]=1.0×10−14. Water's ion product constant at 25°C.
Flashcard 2: What is the [OH−] in a solution with [H+]=1.0×10−4M at 25∘C?
Answer: [OH−]=1.0×10−10M. Use Kw=[H⁺][OH⁻]=1.0×10⁻¹⁴; [OH⁻]=1.0×10⁻¹⁴/1.0×10⁻⁴.
Flashcard 3: What is the pH of a 0.10M strong base that provides 3OH− per formula unit?
Answer: pH=13.48. n=3, so [OH⁻]=3×0.10=0.30 M; pOH=0.52; pH=14-0.52=13.48.
Flashcard 4: What does n represent in [OH−]≈nCbase for a strong base?
Answer: n=moles of OH− produced per mole of base. Counts OH⁻ ions released per base molecule (e.g., 2 for Ba(OH)₂).
Flashcard 5: What assumption is used for a strong base to relate [OH−] to molarity?
Answer: [OH−]≈nCbase. Strong bases fully dissociate; n is OH⁻ ions per base molecule.
Flashcard 6: What is the [OH−] when pOH=9.00?
Answer: [OH−]=1.0×10−9M. Apply [OH⁻]=10⁻ᵖᴼᴴ=10⁻⁹=1.0×10⁻⁹ M.
Flashcard 7: What is the formula that relates pH to [H+]?
Answer: pH=−log[H+]. Negative log converts hydrogen ion concentration to pH scale.
Flashcard 8: What is the relationship between pH and pOH at 25∘C?
Answer: pH+pOH=14.00. At 25°C, the sum always equals 14 due to water's ion product.
Flashcard 9: What is the pOH when pH=3.25 at 25∘C?
Answer: pOH=10.75. Use pH+pOH=14.00; pOH=14.00-3.25=10.75.
Flashcard 10: What is the pH when pOH=1.60 at 25∘C?
Answer: pH=12.40. Use pH+pOH=14.00; pH=14.00-1.60=12.40.
Flashcard 11: What is the formula that relates pOH to [OH−]?
Answer: pOH=−log[OH−]. Negative log converts hydroxide ion concentration to pOH scale.
Flashcard 12: What is the pOH of a solution with [H3O+]=1.0×10−9 M at 25∘C?
Answer: pOH=5.00. pH=−log(1.0×10−9)=9; pOH=14−9=5.
Flashcard 13: What is [H3O+] for a solution with pH=2.50?
Answer: [H3O+]=10−2.50=3.2×10−3 M. Use [H3O+]=10−pH=10−2.50.
Flashcard 14: What is the pH of a 0.015 M solution of Ba(OH)2 at 25∘C?
Answer: pH=12.48. pH=14.00−pOH=14.00−1.52=12.48.
Flashcard 15: What is the pOH of a 0.015 M solution of Ba(OH)2?
Answer: pOH=1.52. pOH=−log(0.030)=−log(3×10−2)=1.52.
Flashcard 16: What is the pH of a 2.0×10−5 M solution of HBr?
Answer: pH=4.70. pH=−log(2.0×10−5)=5−log(2)=4.70.
Flashcard 17: What is [OH−] for a 0.015 M solution of Ba(OH)2?
Answer: [OH−]=0.030 M. Ba(OH)₂ releases 2 OH⁻ per unit: 0.015×2=0.030 M.
Flashcard 18: What is the pH of a 4.0×10−2 M solution of NaOH at 25∘C?
Answer: pH=12.60. pH=14.00−pOH=14.00−1.40=12.60.
Flashcard 19: What is the pOH of a 4.0×10−2 M solution of NaOH?
Answer: pOH=1.40. pOH=−log(4.0×10−2)=2−log(4)=1.40.
Flashcard 20: Identify the pH of pure water at 25∘C.
Answer: pH=7.00. Neutral water has [H3O+]=[OH−]=1.0×10−7 M.
Flashcard 21: What is the pH of a 3.0×10−4 M solution of Ca(OH)2 at 25∘C?
Answer: pH=10.78. [OH−]=2×3.0×10−4=6.0×10−4; pOH=3.22; pH=10.78.
Flashcard 22: State the expression for Kw and its value at 25∘C.
Answer: Kw=[H3O+][OH−]=1.0×10−14. Water autoionization constant at 25°C.
Flashcard 23: Identify the assumption used for strong acids when finding [H3O+].
Answer: Strong acids dissociate ≈100%: [H3O+]≈ acid molarity. Complete dissociation means initial acid concentration equals [H3O+].
Flashcard 24: Identify the assumption used for strong bases when finding [OH−].
Answer: Strong bases dissociate ≈100%: [OH−]≈ base molarity × stoichiometry. Complete dissociation; multiply by OH⁻ per formula unit.
Flashcard 25: What is [H3O+] for a 0.030 M solution of HCl?
Answer: [H3O+]=0.030 M. HCl is monoprotic strong acid, so [H3O+] equals molarity.
Flashcard 26: What is the pH of a 1.0×10−3 M solution of HNO3?
Answer: pH=3.00. pH=−log(1.0×10−3)=3.00 for strong acid HNO₃.
Flashcard 27: State the formula for pH in terms of hydronium concentration.
Answer: pH=−log[H3O+]. Negative log converts small [H3O+] values to manageable pH scale.
Flashcard 28: State the formula for pOH in terms of hydroxide concentration.
Answer: pOH=−log[OH−]. Negative log converts small [OH−] values to manageable pOH scale.
Flashcard 29: What is the relationship between pH and pOH at 25∘C?
Answer: pH+pOH=14.00. At 25°C, this sum equals −log(Kw)=14.00.
Flashcard 30: What is the pH of a solution with [OH−]=1.0×10−12 M at 25∘C?
Answer: pH=2.00. pOH=−log(1.0×10−12)=12; pH=14−12=2.