Unit 1 Oxidising and Reducing Agents

Question 1

Oxidation

Answer 1

An atom loses electrons

Question 2

Reduction

Answer 2

An atom gains electrons

Question 3

Oxidising agent

Answer 3

Oxidise other substances by making them lose electrons
They accept electrons to be reduced
High EN
Power increases down the ECS

Question 4

Reducing agent

Answer 4

Reduce other substances by making them gain electrons
They lose electrons to be oxidised
Low EN
Power increases up the ECS

Question 5

What group has the strongest reducing and oxidising agents

Answer 5

Group 1 has the strongest reducing agents
Groups 7 have the strongest oxidising agent

Question 6

Hydrogen peroxide H2O2, Dichromate CrO72− & Permanganate (MnO4-)

Answer 6

Oxidising agents

Question 7

What can oxidising agents be used for?

Answer 7

Bleaching agent for hair and clothes
Kill bacteria and Fungi
Inactivate viruses

Question 8

What colour change happens when Potassium dichromate gets oxidised

Answer 8

Orange - Green

Question 9

Ion electron equations

Answer 9

If an ion electron equation involves one type of element add e to the less negative side

Al(s) ⟶ Al3+(aq) + 3e−​

Question 10

Complex ion electron equations

Answer 10

Cr2O72−(aq) ⟶ Cr3+(aq)

1. Balance Cr2O72−(aq) ⟶ 2Cr3+(aq)
2. Balance oxygen Cr2O72−(aq) ⟶ 2Cr3+(aq) + 7H2O
3. Balance Hydrogen Cr2O72−(aq) + 14H+ ⟶ 2Cr3+(aq) + 7H2O
4. Balance Charges to less negative side
   Cr2O72−(aq) + 14H+ + 6e ⟶ 2Cr3+(aq) + 7H2O

Question 11

Redox equations

Answer 11

1. Find both equations in the ECS
2. Reverse the one higher in the ECS
3. Balance electrons and combine

Question 12

Self-indicating

Answer 12

Reactant which changes colour to signify endpoint of the reaction

Question 13

Standard solution

Answer 13

A solution with an accurately known concentration