QCE Senior Chemistry U3: Redox (QLD Teachers)

What is reduction?

Reduction is the gain of electrons

What is oxidation?

Oxidation is the loss of electrons

What do oxidation numbers represent?

They represent the gain or loss of electrons.

What is the common oxidation number of Group 1 metals ?

Group 1 is + 1 Including - Li+, Na+

When is Hydrogen's oxidation number not equal to +1?

In metal hydrides, hydrogen has a oxidation number of -1 Including - LiH

For monoatomic ions, how is the oxidation number determined?

The oxidation number is determined by the charge on the ion Eg, Cu2+ has an oxidation number of +2

What happens to the oxidation states when the atom undergoes reduction?

Oxidation state decreases

What molecule has oxidation number of 0?

Elements including - He, Fe, Li, O2

What is the common oxidation number of Group 2 metals?

Group 2 is +2 including - Mg2+, Ca2+

When is Oxygen's oxidation number not equal to -2?

In peroxide (H2O2), oxygen has an oxidation number of -1

What happens to the oxidation states when the atom undergoes oxidation?

Oxidation states increase

Elements in Group 1 and 2 of the periodic table are more likely to - oxidise or reduce?

Oxidise

What is an oxidising agent?

A reactant that causes another reactant to lose electrons and be oxidised and is itself reduced

What occurs to a reducing agent?

Oxidation

What is a REDOX reaction?

One where both reduction and oxidation occurs simultaneously

Will atoms with high electronegativities tend to oxidise or reduce?

They will undergo reduction

What should be the sum of the oxidation numbers in a neutral compound equal?

zero

What is a half-equation?

An equation that represents either oxidation or reduction

What is an overall redox equation made up of?

The oxidation and reduction half equations and added together

What does OILRIG stand for?

Oxidation is loss of electrons, reduction is gain of electrons

The sum of the oxidation numbers in a polyatomic ion should equal what?

The charge on the ion

Atoms from what area of the periodic table have multiple oxidation states?

Transition metals

What is a spectator ion?

An ion that exists in the same state on the reactant and product side of a reaction. Its oxidation state does not change.

What does RED CAT represent?

Reduction always occurs at the cathode

What does AN OX represent?

Oxidation always occurs at the anode

Can oxidation happen by itself?

No, reduction must also occur

What is a corrosion reaction?

Process where metal reacts with chemicals in the atmosphere. The metal must be more stable as an ion than a solid

What type of chemical reactions are redox reactions?

Single displacement, combustion, electrochemical cells, corrosion

When elements lose their valence electrons, do they act as oxidising or reducing agents?

The elements are oxidised and act as reducing agents