Volts Don’t Scale; Kilojoules Do

You'll learnhow to get E°_cell by subtraction, convert it to ΔG° with −nFE°, and see why doubling the equation changes only one of them.

A voltmeter on a cell reads 1.10 V whether the cell is the size of a coin or the size of a car. Double the balanced equation and the needle does not move, while the energy available doubles exactly. Twelve short steps; press Next for each one.

12 STEPS · 6 QUICK CHECKS · E°_cell = E°_cath − E°_anode · ΔG° = −nFE° · v2

the gap between two table entries · and what it is worth in kilojoules

Before you start

What you're looking at

The cell from 9.8, with a voltmeter wired into the wire across the top.

The question

The meter reads 1.10 V. Where does that number come from, and what is it worth in kilojoules?

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