oxidation, reduction and redox reactions

Question 1

when oxidising you … electrons, when reducing you … electrons

Answer 1

lose
gain

Question 2

what are reducing agents

Answer 2

they lose electrons and they are oxidised themselves

Question 3

what are oxidising agents

Answer 3

they gain electrons and are reduced themselves

Question 4

uncombined elements oxidation number?

Answer 4

always 0

Question 5

ions oxidation number?

Answer 5

always same as charge on number

Question 6

group 1 oxidation number?

Answer 6

always +1

Question 7

group 2 oxidation number?

Answer 7

always +2

Question 8

aluminium oxidation number?

Answer 8

always +3

Question 9

hydrogen oxidation number?

Answer 9

+1 except in hydrides where it is -1

Question 10

what is a hydride

Answer 10

when a hydrogen is bonded to a metal like Na

Question 11

chlorine oxidation number?

Answer 11

-1 except in a compound of F or O

Question 12

fluorine oxidation number?

Answer 12

always -1

Question 13

oxygen

Answer 13

-2, except in peroxides where its -1, and fluorine where its +2

Question 14

what is a peroxide

Answer 14

when there is an atom for every oxygen eg H2O2

Question 15

how to figure out whether it is a reduction or oxidation from oxidation number

Answer 15

reduction- decrease in oxidation number
oxidation- increase in oxidation number

Question 16

rules for balancing half equations

Answer 16

write down reaction
balance any arms apart from hydrogen or oxygen
balance any oxygens with H2O
balance any hydrogens with H+ ions
balance any charges with electrons