Redox reactions

Question 1

Define: redox reaction

Answer 1

involves the transfer of electrons from one substance to another, through simultaneous reduction and oxidation reactions. Indicated by change in oxidation number of a substance.

Question 2

Define: oxidation

Answer 2

when the reactant loses electrons

Question 3

Define: reduction

Answer 3

when the reactant gains electrons

Question 4

Define: oxidising agent

Answer 4

a reactant that causes another reaction to be oxidised (but is reduced itself)

Question 5

Define: reducing agent

Answer 5

a reactant that causes another reactant to be reduced (but is oxidised itself)

Question 6

How do we balance half equations?

Answer 6

First with superscripts so we have the same number of an atom/ion.
Then with electrons, so we have the same charge - taking into account the balanced number of atoms/ions

Question 7

How do we do overall redox equations?

Answer 7

Equate the electrons then sub in. If a compound is formed, we write the compound and not the ions.

Question 8

can overall redox equations come from complex half equations?

Answer 8

Yes

Question 9

Define: spontaneous/naturally occurring reactions

Answer 9

reactions that occur in cells or when directly mixed. Indicated by positive potential difference value.

Question 10

Under what conditions do spontaneous reactions occur?

Answer 10

One substance is oxidised, one is reduced
the oxidised substance is lower on the electrochemical series
OTHERWISE NO REACTION

Question 11

Limitations of predicting spontaneous redox reactions from electrochemical series?

Answer 11

Doesn’t show rate of reaction

Only apply under standard conditions, so half cell potentials and order of half equations can change.