redox

Question 1

oxidation

Answer 1

increase in oxidation number

Question 2

reduction

Answer 2

decrease in oxidation number

Question 3

uncombined elements

Answer 3

0

Question 4

ions

Answer 4

same as charge on ion
(e.g cl- = -1)

Question 5

group 1

Answer 5

+1

Question 6

group 2

Answer 6

+2

Question 7

aluminium

Answer 7

+3

Question 8

hydrogen

Answer 8

+1 (excepts in hydrides where its -1)
hydride = metal bonded to H (e.g NaH)

Question 9

chlorine

Answer 9

-1

Question 10

flourine

Answer 10

-1

Question 11

oxygen

Answer 11

-2 (except in perioxides = -1 and +2 in OF2)

Question 12

when writing oxidation numbers remember to…

Answer 12

put a + or - in front of the answer when writing the answer

Question 13

steps for writing half equations

Answer 13

1) write equation given
2) balance any atoms
3) balance any oxygens with H20
4) balance any hydrogens with H+
5) balance any charges with** e-** (always add e- to the more positive side)

Question 14

Explain how oxides of nitrogen are formed in engines.

Answer 14

reaction of nitrogen and oxygen** from the air**
at high temperatures

Question 15

State the meaning of the term heterogeneous catalyst.

Answer 15

Catalyst in different phase which speeds up reaction without being used up