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Flashcards in Redox Deck (28)
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1

In terms of oxygen define oxidation

Gaining oxygen

2

In terms of oxygen define reduction

Loss of oxygen

3

In terms of oxygen define an oxidising agent

Provides oxygen and is in itself reduced

4

In terms of oxygen define a reducing agent

Removes oxygen and is in itself oxidised

5

In terms of hydrogen define oxidation

Loss of hydrogen

6

In terms of hydrogen define reduction

Gain of hydrogen

7

In terms of hydrogen define an oxidising agent

Removes hydrogen and is in itself reduced

8

In terms of hydrogen define a reducing agent

Gains hydrogen and is in itself oxidised

9

In terms of electrons define oxidation

Loss of electrons

10

In terms of electrons define reduction

Gain of electrons

11

In terms of electrons define an oxidising agent

Gains electrons and is in itself reduced

12

In terms of electrons define a reducing agent

Loss of electrons and is in itself oxidised

13

What is the oxidation number of an uncombined element or one combined with itself?

Always zero

14

What is the oxidation number of a simple ion (with only 1 element)?

Equal to its charge

15

What is the oxidation number of all group 1 elements?

Always +1

16

What is the oxidation number of all group 2 elements?

Always +2

17

What is the oxidation number of hydrogen?

+1, except in metal hydrides of group 1 and 2 wher e it becomes -1

18

What is the oxidation number of oxygen?

-2, except in peroxides (e.g. H2O2) where it becomes -1, and oxygen fluoride where it becomes +2

19

What is the oxidation number of fluorine?

Always -1

20

What is the oxidation number of chlorine?

Usually -1 (like in metal chlorides), but it changes when other non-metals are present

21

What is the oxidation number of a compound ion?

The sum of the oxidation numbers is equal to the charge on the ion

22

What is the definition of oxidation number?

The charge that a species would have if it was a simple ion

23

What is a disproportionation reaction?

The simultaneous oxidation and reduction of an element in a single species

24

Points for writing half equations

- reactions on the left and products on the right
- state symbols are usually included
- for an oxidation reaction, electrons can be shown on the left or the right
- for a reduction reaction, electrons are shown on the left
- the reaction must balance for charge

25

Writing a half equation for reduction (under acidic conditions)

After putting in the correct number of electrons gained, add H+ on the left and water on the right, then balance

26

Writing a half equation for oxidation (under alkaline conditions)

After putting in the correct number of electrons lost, add OH- on the left hand side and H2O on the right, then balance the charge by adding extra OH- ions

27

Combining half equations using the ion-electron method

Multiply one or both of the half equations so that the number of electrons lost or gained becomes the same in both equations, then add the two together to get the overall equation

28

Combining half equations using the oxidation number method

number of atoms of A x change in oxidation number of A = number of atoms of B x change in oxidation number of B