redox

Question 1

what is a redox reaction

Answer 1

when reduction and oxidation occur at the same time

Question 2

what is oxidation

Answer 2

losing electrons

Question 3

what is reduction

Answer 3

gaining electrons

Question 4

4 rules when assigning oxidative numbers

Answer 4

1. uncombined elements have an oxidative number of 0 e.g. Cl2, O2, Zn
2. oxidative numbers in a compound must add up to 0
3. oxidative number of a monoatomic ion is equal to the charge e.g. Cl- = -1
4. 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

Question 5

3 specific rules regarding oxidative numbers

Answer 5

1. group 7 elements are always 1- except when attached to fluorine, where they are +1, fluorine is alway -1
2. hydrogen is always 1+ except when it forms a metal hydride becoming -1e.g. NaH
3. oxygen is always 2- except when it forms a peroxide becoming -1 e.g.H2O2

Question 6

what is an oxidising agent

Answer 6

An electron acceptor.
a species which causes other elements to be oxidised, itself being reduced

Question 7

what is a reducing agent

Answer 7

An electron donor.
a species which causes other elements to be reduced, itself being oxidised