1
Q
what is a redox reaction
A
when reduction and oxidation occur at the same time
2
Q
what is oxidation
A
losing electrons
3
Q
what is reduction
A
gaining electrons
4
Q
4 rules when assigning oxidative numbers
A
- uncombined elements have an oxidative number of 0 e.g. Cl2, O2, Zn
- oxidative numbers in a compound must add up to 0
- oxidative number of a monoatomic ion is equal to the charge e.g. Cl- = -1
- oxidative number of a polyatomic ion is equal to the charge of the ion e.g. CO3^2-. C= +4, O= -2(*3 =6)
= -2
5
Q
3 specific rules regarding oxidative numbers
A
- group 7 elements are always 1- except when attached to fluorine, where they are +1, fluorine is alway -1
- hydrogen is always 1+ except when it forms a metal hydride becoming -1e.g. NaH
- oxygen is always 2- except when it forms a peroxide becoming -1 e.g.H2O2
6
Q
what is an oxidising agent
A
An electron acceptor.
a species which causes other elements to be oxidised, itself being reduced
7
Q
what is a reducing agent
A
An electron donor.
a species which causes other elements to be reduced, itself being oxidised
