AP Chemistry Flashcards: Acid Base Titrations

What this deck covers

This deck focuses on Acid Base Titrations, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Which option describes a buffer solution?

Answer: Resists changes in pH upon addition of acid or base. Contains conjugate acid-base pair to maintain pH stability.

Flashcard 2: What is the equivalence point in a titration curve?

Answer: Where moles of acid equal moles of base. Stoichiometric neutralization point on titration curve.

Flashcard 3: Calculate the pH of a 0.01 M HCl solution.

Answer: pH = 2. Strong acid: pH = $-\log(0.01) = -\log(10^{-2}) = 2$.

Flashcard 4: What is the pH of a neutral solution at 25°C?

Answer: $pH = 7$. Equal concentrations of $H^+$ and $OH^-$ at 25°C.

Flashcard 5: Choose the correct pH range for phenolphthalein.

Answer: 8.2 to 10.0. Indicator's transition range for color change.

Flashcard 6: What is the pH of a 0.1 M NH₃ solution if $K_b = 1.8 \times 10^{-5}$?

Answer: pH ≈ 11.1. Use $K_b$ expression: $[OH^-] = \sqrt{K_b \times C}$ then find pH.

Flashcard 7: Calculate the volume of 0.1 M NaOH needed to neutralize 50 mL of 0.1 M HCl.

Answer: 50 mL. Equal molarity and volume means 1:1 mole ratio requires equal volume.

Flashcard 8: Which indicator is commonly used for strong acid-strong base titrations?

Answer: Phenolphthalein. Changes color at pH 8.2-10, ideal for strong acid-base endpoints.

Flashcard 9: State the formula for converting pH to hydrogen ion concentration.

Answer: $[\text{H}^+] = 10^{-\text{pH}}$. Inverse relationship: pH is negative log of $[H^+]$.

Flashcard 10: In a titration, what is the titrant?

Answer: The solution added from the burette. Standard solution delivered from burette during analysis.

Flashcard 11: Find and correct the error: 'The equivalence point is always at pH 7.'

Answer: Not always; depends on the strength of acid and base. Only true for strong acid-strong base; weak acids/bases differ.

Flashcard 12: What is the color change of phenolphthalein in basic solutions?

Answer: Colorless to pink. Phenolphthalein is colorless in acid, pink in base.

Flashcard 13: Identify the primary characteristic of a weak acid.

Answer: Partially ionizes in solution. Incomplete dissociation results in equilibrium with undissociated acid.

Flashcard 14: What is the role of a pipette in a titration?

Answer: To measure and transfer a specific volume of solution. Precision instrument for accurate volume transfer.

Flashcard 15: What is the purpose of a titration in acid-base chemistry?

Answer: To determine the concentration of an unknown solution. Uses known titrant to find unknown concentration via stoichiometry.

Flashcard 16: Which equation relates pH and pOH?

Answer: $\text{pH} + \text{pOH} = 14$. Fundamental relationship for aqueous solutions at 25°C.

Flashcard 17: What is the definition of a titrant?

Answer: A solution of known concentration used in titration. Standard solution added from burette to determine analyte concentration.

Flashcard 18: Which option best describes a titration curve?

Answer: Graph of pH versus volume of titrant added. Visual representation showing pH changes during titration process.

Flashcard 19: What is the effect of a strong base on the pH of a buffer?

Answer: Slight increase in pH. Buffer components consume added base, minimizing pH change.

Flashcard 20: What is the effect of dilution on the pH of a strong acid?

Answer: Increases the pH. Dilution decreases $[H^+]$, raising pH toward neutral.

Flashcard 21: What happens to pH when a strong acid is added to a buffer?

Answer: Slight decrease in pH. Buffer components consume added acid, minimizing pH change.

Flashcard 22: Which term describes the solution whose concentration is to be determined during titration?

Answer: Analyte. The unknown solution whose concentration is being determined.

Flashcard 23: State the formula for calculating molarity.

Answer: $M = \frac{\text{moles of solute}}{\text{liters of solution}}$. Defines concentration as moles of solute per liter of solution.

Flashcard 24: Which acid-base pair has a higher pH at the equivalence point: strong acid-weak base or weak acid-strong base?

Answer: Weak acid-strong base. Weak acid-strong base gives basic equivalence point (pH > 7).

Flashcard 25: Calculate the moles of HCl in 25 mL of 0.1 M solution.

Answer: 0.0025 moles. Convert volume to L (0.025 L), multiply by molarity (0.1 M).

Flashcard 26: What type of reaction occurs during a titration?

Answer: Neutralization. Acid and base react to form salt and water.

Flashcard 27: What is the pH at the equivalence point for a strong acid-strong base titration?

Answer: pH = 7. Equal amounts of strong acid and base neutralize to neutral pH.

Flashcard 28: Identify the endpoint in a titration.

Answer: The point at which the indicator changes color. Visual signal used to determine when to stop adding titrant.

Flashcard 29: Find the pH of a solution with $[\text{OH}^-] = 10^{-3}$ M.

Answer: pH = 11. pOH = $-\log(10^{-3}) = 3$, so pH = $14 - 3 = 11$.

Flashcard 30: What is the role of a burette in a titration?

Answer: To deliver a precise volume of titrant. Graduated tube allows controlled addition and volume measurement.

Flashcard 31: What is the primary characteristic of a strong acid?

Answer: Completely ionizes in solution. Dissociates nearly 100% in aqueous solution.

Flashcard 32: What is the endpoint of a titration?

Answer: The point where the indicator changes color. Observable color change indicating approximate equivalence point.

Flashcard 33: What is a standard solution?

Answer: A solution of known concentration. Precisely known concentration for quantitative analysis.

Flashcard 34: Determine the pH of a solution with $[\text{H}^+] = 10^{-6}$ M.

Answer: pH = 6. pH is defined as $-\log[H^+] = -\log(10^{-6}) = 6$.

Flashcard 35: Identify the formula to convert pOH to hydroxide ion concentration.

Answer: $[\text{OH}^-] = 10^{-\text{pOH}}$. Inverse relationship: pOH is negative log of $[OH^-]$.

Flashcard 36: What is the relationship between $K_a$, the acid dissociation constant, and acid strength?

Answer: Higher $K_a$ indicates a stronger acid. Larger $K_a$ means greater ionization and stronger acid.

Flashcard 37: Identify the primary purpose of an indicator in a titration.

Answer: To signal the endpoint of the titration. Color change marks approximate equivalence point.

Flashcard 38: State the formula to find pOH from hydroxide ion concentration.

Answer: $\text{pOH} = -\text{log}[\text{OH}^-]$. Negative logarithm relationship for hydroxide concentration.

Flashcard 39: Calculate the pOH of a 0.01 M NaOH solution.

Answer: pOH = 2. Strong base: pOH = $-\log(0.01) = 2$.