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Final Calculation Set

  • Time: 20–25 minutes
  • No calculator for simple logs (AP style)
  • Show setup (very important)

Question 1 (pH – Basic)

What is the pH of 1.0 × 10⁻³ M HCl?

  1. 2
  2. 3
  3. 4
  4. 11
Show answer

Correct answer: B

Why: pH = -log(10⁻³) = 3

Trap: Don’t overthink logs

Fix: Exponent = pH

Question 2 (pOH → pH)

If pOH = 5, what is pH?

  1. 5
  2. 7
  3. 9
  4. 14
Show answer

Correct answer: C

Why: pH + pOH = 14 → pH = 9

Trap: Forgetting formula

Fix: Always: pH + pOH = 14

Question 3 (Dilution)

A 1.0 M acid is diluted to 0.10 M. What happens to pH?

  1. increases by 1
  2. decreases by 1
  3. no change
  4. doubles
Show answer

Correct answer: A

Why: 10× dilution → pH increases by 1

Trap: Mixing concentration vs pH

Fix: Each factor of 10 → ±1 pH

Question 4 (K Expression)

For:
A ⇌ B

If [A] = 2.0 M and [B] = 4.0 M, what is K?

  1. 0.5
  2. 2
  3. 4
  4. 8
Show answer

Correct answer: B

Why: K = [B]/[A] = 4/2 = 2

Trap: Reversing ratio

Fix: Products / Reactants

Question 5 (ICE Table Logic – Conceptual Math)

If K = 100, what does this mean?

  1. mostly reactants
  2. mostly products
  3. equal amounts
  4. no reaction
Show answer

Correct answer: B

Why: Large K → products favored

Trap: Thinking rate vs equilibrium

Fix: K = position, not speed

Question 6 (Rate Factor)

If concentration doubles, reaction rate:

  1. halves
  2. doubles
  3. stays same
  4. stops
Show answer

Correct answer: B

Why: More particles → more collisions

Trap: Overcomplicating

Fix: More concentration → faster rate

Question 7 (ΔG)

Which indicates a spontaneous reaction?

  1. ΔG > 0
  2. ΔG = 0
  3. ΔG < 0
  4. ΔH > 0
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Correct answer: C

Why: Negative ΔG → spontaneous

Trap: Confusing ΔH and ΔG

Fix: ΔG decides spontaneity

Question 8 (Pressure + Moles)

For:
2A(g) ⇌ B(g)

If pressure increases, what happens?

  1. shift left
  2. shift right
  3. no change
  4. depends
Show answer

Correct answer: B

Why: Left = 2 moles, Right = 1 → shift right

Trap: Not counting moles

Fix: Pressure ↑ → fewer moles

Question 9 (pH of Diluted Base)

If a base is diluted, what happens to pH?

  1. increases
  2. decreases
  3. no change
  4. becomes neutral
Show answer

Correct answer: B

Why: [OH⁻] decreases → less basic → pH decreases

Trap: Mixing acid logic

Fix: Dilute base → pH ↓

Question 10 (Log Thinking)

Which has lowest pH?

  1. 10⁻²
  2. 10⁻³
  3. 10⁻⁴
  4. 10⁻⁵
Show answer

Correct answer: A

Why: Higher [H⁺] → lower pH

Trap: Confusing exponent direction

Fix: Less negative exponent = stronger acid

FRQ – FINAL FRQ (Calculation Style)

  • A solution has [H⁺] = 1.0 × 10⁻⁶ M.
  • Calculate pH
  • State if solution is acidic, basic, or neutral
Show answer

Perfect Answer:
pH = -log(1.0 × 10⁻⁶) = 6
Since pH < 7, the solution is acidic.