Playbook
Electrochemistry
122 q - 2.88/paper - 9% HARD. The one Chemistry chapter with HARD load — ten Nernst questions on one page.
- Questions in the bank
- 122
- q/paper (2024–25 papers)
- 2.88
- Tagged HARD
- 9%
- Subtopics
- 5
Strand: Calculate
When you’ll see it
A cell and its emf, electrode potentials at non-standard concentration, a conductivity or cell constant, or a charge passed and a mass deposited.
How this chapter is tested
122 q at 2.88 a paper, 9% HARD — the only Chemistry chapter with real HARD load, and it sits on one page. Galvanic Cells, EMF, Nernst Equation and Thermodynamics is 48 questions, and ten of them are HARD: all Nernst — the potential of an electrode at 0.1 M or 0.01 M, or how far the emf moves when one ion's concentration changes tenfold.
The other four pages are one line each. Faraday: m = ZIt = (M/nF)·It. Conductivity: κ = (1/R)·cell constant, and Λm = κ × 1000/c. Kohlrausch: Λ°m of a weak electrolyte from strong ones. Batteries (9 q) are recall.
The sub-skills
The distinct skills inside the chapter, in the order to learn them.
E°cell
E°cell = E°cathode − E°anode (reduction potentials). ΔG° = −nFE°.
Nernst
E = E° − (0.0592/n) log Q at 25 °C. For M(n+)|M: E = E° + (0.0592/n) log[M(n+)].
Conductivity
κ = G* / R; Λm = 1000κ/c (S cm² mol⁻¹); α = Λm/Λ°m.
Faraday
1 F = 96500 C per mole of electrons; mass = (M/nF) × charge.
Traps to expect
Distractor shapes this chapter reuses. The Traps page covers the patterns that cut across chapters.
Dropping n in the Nernst term
For Zn²⁺, n = 2, so a tenfold change moves E by 0.0296 V, not 0.0592 V. The n = 1 answer is printed.
Reversing the subtraction
E°cell = E°(cathode) − E°(anode), using reduction potentials for both. Taking the anode minus the cathode gives the right size with the wrong sign.
Learn it before you drill it
This chapter has full teaching notes — foundations, worked examples, self-checks and a per-subtopic mastery checkpoint. Read the notes once, then drill subtopic by subtopic below.
Electrochemistry notesDrill every electrochemistry question
122 questions from the bank, scoped to 5 bundled subtopics.
Drill one subtopic at a time
The 5 subtopics this playbook covers, in catalog order.
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