chem last test study

1: Identify a Redox Reaction

- Redox = electrons are transferred.

- If oxidation numbers change, it's redox.

- Metals -> ions and ions -> metals = redox clues.

LT 2: Determine What's Oxidized & Reduced

- LEO says GER: Lose Electrons = Oxidation, Gain Electrons = Reduction.

- Oxidation # UP = Oxidation. Oxidation # DOWN = Reduction.

LT 3: Form Basic Half Reactions

- Split into Oxidation (loss of e-) and Reduction (gain of e-).

LT 4: Write & Balance Half Reactions

- Balance atoms -> O (H2O) -> H (H+) -> Charge (e-).

LT 5: Calculate Ecell

Ecell = Ecathode - Eanode

- Positive Ecell = spontaneous.

- Anode: oxidation; Cathode: reduction.

LT 6: Set Up a Galvanic Cell

- Converts chemical to electrical energy.

- Anode (oxidation, negative), Cathode (reduction, positive), Salt bridge.

- Electrons flow Anode -> Cathode.

LT 7: Electrolytic Cell & Electroplating

- Uses electric power to force non-spontaneous reactions.

- Anode = oxidation, Cathode = reduction (but needs power source).

LT 8: Equilibrium, Gibbs, and Ecell

Delta G = -nFEcell

- Positive Ecell -> Negative Delta G -> K > 1 (spontaneous)

- Negative Ecell -> Positive Delta G -> K < 1 (non-spontaneous)

Quick Summary Table

Positive Ecell? Spontaneous, Delta G negative, K > 1

Negative Ecell? Non-spontaneous, Delta G positive, K < 1