chapter 7- oxidation, reduction and redox reactions

Question 1

what is oxidation and reduction in terms of electrons

Answer 1

oxidation is loss of electrons
reduction is gain of electrons

Question 2

what are oxidising and reducing agents

Answer 2

oxidising agents- accept electrons
reducing agents- give away electrons

Question 3

what are the rules to follow when working out oxidation states

Answer 3

1. uncombined elements have an oxidation state of 0
2. some elements always have the same oxidation state in all their compounds
3. The sum of all the oxidation states in a compound = 0, since all compounds are electrically neutral.
4. The sum of the oxidation states of a complex ion, such as NH4+ or SO4 2-, equals the charge on the ion
5. in a compound the most electronegative element always has a negative oxidation state

Question 4

what is the oxidation state in a compound of:

• hydrogen
• group 1
• group 2
• aluminum
• oxygen
• fluorine
• chlorine

Answer 4

• hydrogen +1 (except in metal hydrides e.g NaH = -1)
• group 1 +1
• group 2. +2
• aluminum + 3
• oxygen -2 (except in peroxides =-1/ compound OF2 = +2)
• fluorine - 1
• chlorine -1 (except in compounds with F and O = positive values)