Redox

Question 1

What is oxidation?

Answer 1

Gain of oxygen
Loss of hydrogen
Loss of electrons
Increase in oxidation number

Question 2

What is reduction?

Answer 2

Loss of oxygen
Gain of hydrogen
Gain of electrons
Decrease in oxidation number

Question 3

What is a redox reaction?

Answer 3

When oxidation and reduction occur simultaneously in same reaction.

Question 4

What is a displacement reaction?

Answer 4

When more reactive element displaces less reactive element from its compound solution.

Question 5

What is an example of a displacement reaction?

Answer 5

Iron + Copper sulfate > Iron sulfate + Copper

Fe (s) + CuSO4 (aq) > FeSO4 (aq) + Cu (s)

Question 6

What is a reducing agent?

Answer 6

Species which has been oxidised and lost electrons in redox reaction.

Question 7

What can be said about the reducing agent in a redox reaction?

Answer 7

Is an electron donor

Question 8

What is an oxidising agent?

Answer 8

Species which has been reduced and gained electrons.

Question 9

What can be said about the oxidising agent in a redox reaction?

Answer 9

Is an electron acceptor

Question 10

How can oxidation states be used to interpret redox reactions?

Answer 10

Assigned to atoms in molecules or ions to show many electron atom has used in bonding.

Question 11

What are the rules for working out oxidation states?

Answer 11

1 - Oxidation state of element always 0.
2 - In compounds, total sum of oxidation states always 0.
3 - In ions, total sum of oxidations states equals charge of ion.

Question 12

What are the common oxidation states in group 1 elements?

Answer 12

+1

Question 13

What are the common oxidation states in group 2 elements?

Answer 13

+2

Question 14

What is the common oxidation state for hydrogen?

Answer 14

+1 (except when joined to very electropositive metal - metal hydrides them -1)

Question 15

What is the common oxidation state for fluorine?

Answer 15

-1

Question 16

What is the common oxidation state for chlorine?

Answer 16

-1 (except when combined with O or F)

Question 17

What is the common oxidation state for oxygen?

Answer 17

-2 (except in peroxides, then -1)

Question 18

What is a disproportionation reaction?

Answer 18

Oxidation and reduction of the same element in the same reaction.

Question 19

What is an example of a disproportionation reaction?

Answer 19

3MnO4 2- + 4H + > 2MnO4 - + MnO2 + 2H2O
+6 -2 +1 +7 -2 +4 -2 +1 -2

Question 20

What is the method for writing out half equations?

Answer 20

K - key element (amount / balance)
O - oxygen add water to opposite side
H - hydrogen ions
E - electrons to side where are less
S - state symbols