Oxidation, Reduction and Redox Equations

Question 1

Describe oxidation..

Answer 1

• loss of electrons
  -gaining oxygen
  -e- after arrow

Question 2

Describe reduction..

Answer 2

• gain of electrons
  -gain of hydrogen
  -e- before arrow

Question 3

What is a reducing agent?

Answer 3

Reducing agents reduces other species but become oxidised themselves

Question 4

What is an oxidising agent?

Answer 4

Oxidise other species and are reduced themselves.

Question 5

What are the exceptions in oxidation numbers?

Answer 5

1) Hydrogen is +1 except in hydrides

2) chlorine is -1 except if in a compound with F and O it would have a positive value

3)

Question 6

What sort of element takes priority in working out oxidation numbers?

Answer 6

The most electronegative element

Question 7

do the little numbers count when figuring out oxidation numbers?

Answer 7

yuhhh

eg) NH3

so 1x 3

Question 8

What is the oxidation number referring to?

Answer 8

ONE ELEMENT

so if diatomic divide by 2

Question 9

What happens to oxidation number if reduction is happening?

Answer 9

decrease in oxidation number

Question 10

What happens to oxidation number if oxidation is happening?

Answer 10

increase in oxidation number

Question 11

How to write a balanced half-equation?

Answer 11

1) write down species before and after a reaction

2) balance any atoms apart from oxygen and hydrogen

3) balance oxygens with water

4) balance hydrogens with H+ ions

5) balance charges with electrons

Question 12

How to combine half equations?

Answer 12

1) x to make sure electrons amount is the same

2) then cancel out electrons

3) combine electrons depending what is before the arrow and after

Question 13

What is a redox reaction?

Answer 13

A chemical reaction where oxidation and reduction happen at the same time.