Potentiometry, Ion-Selective Electrodes and Voltammetry · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Electrodes that measure

Science · Chemistry · ages 21-22
Name ______________________   Date ____________

  1. How do you get the standard cell voltage from the table?

    • Anode value minus cathode value
    • The two values multiplied
    • Cathode value minus anode value

  2. Why does every measurement pair your electrode with a reference electrode?

    • A reading needs two electrodes
    • The solvent demands a partner
    • Two electrodes double the current

  3. A glass electrode builds a potential that tracks pH.

    Circle one:   True   False

  4. What marks a reversible couple on a voltammogram?

    • A single peak with no return
    • Equal peaks, steady spacing
    • A flat line at zero current

  5. What does a selectivity coefficient tell you?

    • How fast the electrode dissolves
    • How warm the sample may be
    • How much a second ion interferes

  6. The peaks of a voltammogram are unequal. What should you suspect?

    • The oxidised form changed
    • The paper ran out of ink
    • The sweep ran backwards in time

  7. Why do stripping methods reach such tiny traces?

    • They gather the target first, then measure
    • They sweep the potential faster than thought
    • They remove the reference electrode

  8. A student reports a single electrode potential with no reference. What is wrong?

    • The sign was written backwards
    • Lone potentials cannot be read
    • The units must be grams
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Electrodes that measure W1-mt_7sLJXqFfWR-s1

  1. Cathode value minus anode value · Subtract the anode number from the cathode number; a positive result runs alone.
  2. A reading needs two electrodes · A lone potential has no meaning, so a fixed reference completes the pair.
  3. True · The meter reads that potential against the reference and converts it.
  4. Equal peaks, steady spacing · Steady spacing plus matched heights is the reversible signature.
  5. How much a second ion interferes · It weighs the intruder against the target, so you can judge the interference.
  6. The oxidised form changed · A changed product shrinks the return wave, so the peaks stop matching.
  7. They gather the target first, then measure · Collecting first turns a whisper of sample into a clear signal.
  8. Lone potentials cannot be read · Only a difference against a fixed reference can ever be read.
Worksheet · LightMySky