1.7 Oxidation, Reduction & Redox Equations Flashcards
What is oxidation in terms of electrons?
Process where there is an electron loss
What is reduction is terms of electrons?
Process where there is an electron gain
What is oxidation in terms of hydrogen
Process where there is a hydrogen loss
What is reduction in terms of hydrogen
Process where there is a hydrogen gain
What is oxidation in terms of oxygen?
Process where there is an oxygen gain
What is reduction in terms of oxygen?
Process where there is an oxygen loss
What is an oxidising agent?
Compound that is an electron/hydrogen acceptor or oxygen donor
What is a reducing agent?
Compound that is an electron/hydrogen donor or oxygen acceptor
What happens when a reducing agent loses electrons?
It becomes oxidised
i.e. Ca –> Ca2+ + 2e-
What happens when an oxidising agent gains electrons?
It becomes reduced
i.e. 1/2 O2 + 2e- –> O2-
How does oxidation change an oxidation number?
increases
How does oxidation change an oxidation number?
Increases
How does reduction change an oxidation number?
Decreases
What is the oxidation number of an uncombined element? And give an example.
- Cl2, F2 etc.
What is the oxidation number of an ion? And give an example.
It’s the overall charge of the ion. Cl- is -1.
What is the oxidation number of Group 1 Metals? And give an example.
ALWAYS +1. KCl.
What is the oxidation number of Group 2 Metals? And give an example.
ALWAYS +2. MgO.
What is the oxidation state of Aluminium? And give an example.
ALWAYS +3. Al2O3.
What is the oxidation number of Hydrogen? And give an example.
Usually +1. Except in hydrides (combined with metal), then it’s -1. KF or NaH
What is the oxidation number of Chlorine? And give an example.
Usually -1. Except with F/O. KCl or in ClF3 it’s +3.
What is the oxidation number of Fluorine? And give an example.
ALWAYS -1. Highest oxidation strength.
What is the oxidation number of Oxygen? And give an example.
Usually -2. Except in peroxides & +2 in OF2. Li2O or in H2O2 it’s -1.
What are half-equations?
Show reduction and oxidation stages in two separate equations.
What must half-equations always include?
Electrons.
What is the process of forming half equations?
- Write species before and after
- Balance any atoms (NOT O/H)
- Balance Oxygen atoms with H2O
- Balance Hydrogen atoms with H+
- Balance charges with electrons (e-)
How do you identify an oxidation half-equation?
Electrons on RHS.
How do you identify a reduction half-equation?
Electrons on LHS
What is the sycronym to remember oxidation and reduction?
Oxidation Reduction
Is Is
Loss Gain
How do you create a full-equation from two half-equations?
Balance electrons on both sides and combine equations cancelling out electrons.
TIP: fully simplify every compound
