R3.2.14 Cell potential and Gibbs free energy (HL)

This video covers how to calculate Gibbs's energy from Ecell.

[@alisgevorgyan3891]

Perfect timing

[@AgentCharles522002]

🔥

[@samuellowe9949]

W

[@god9331]

if u see for example that 3Ag+ transfer their electrons to Al to form Al3+, can we assume that n=3 without balancing the half equaions for e-

[@MSJChem]

Yes

[@heleen2366]

at 1:22 - for calculating the cell potential of the reaction wouldn't we have to use the reverse reaction for zinc ions being reduced into zinc atoms, so +0.76 - (+0.15) = 0.61 instead of 1.1 volts?

[@MSJChem]

No, use the values exactly as they are shown in the data booklet.

[@nicole2539]

If the units of the variables in the equation G = -nFE are n: mol, F: C/mol, E: J/C (volts) then how does G have a unit of J/mol? Shouldn't it have a unit of only J? Is it more conceptual as in joules per every mole of Zn and Cu that react?

[@MSJChem]

The units of n are not mol (in fact it has no unit) so the units of delta G are J/mol.

[@khronicks1708]

@@MSJChem Hi sir, I've been watching Richard Thornley's videos, he said the units are joules, I agree with nicole and I'm really confused, please can you explain why n doesn't have units?

[@MSJChem]

Units of delta G are J/mol. n has no units because it is the mol of electrons transferred and cancels out.

[@karhukivi]

This is late - I'm sure you know the answer by now! The "n" = 2 means "2 moles" so it has no units, i.e. it is just a number.