7. Oxidation, Reduction & Redox Flashcards Preview

AQA A Level Physical Chemistry > 7. Oxidation, Reduction & Redox > Flashcards

Flashcards in 7. Oxidation, Reduction & Redox Deck (40)
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1

What is oxidation?

Loss of electrons, gain of oxygen

2

What is reduction?

Gain of electrons, loss of oxygen

3

What is a redox reaction?

In any reaction where an element is oxidised, and another must be reduced

4

What happens if an element itself is oxidised?

It must reduce the other element (by donating electrons)

5

What is the element that is oxidised known as?

The reducing agent (reductant)

6

Why is the element that is oxidised known as the reducing agent?

It must reduce the element by donating electrons

7

What happens if an element itself is reduced?

It must oxidise the other element (by accepting electrons)

8

What is the element that is reduced known as?

The oxidising agent (oxidant)

9

Why is the element that is reduced known as the oxidising agent?

It must oxidise the element by accepting electrons

10

What is used when it is unclear which element has been oxidised and which reduced?

Oxidation number/state of an element

11

Are S block metals oxidising or reducing agents?

Reducing - they lose electrons in reactions and so are oxidised

12

Do s block metals have positive or negative oxidation numbers?

Positive

13

Which elements will need to have their oxidation numbers worked out?

P and d block elements

14

Why do p and d block elements have to have their oxidation numbers worked out?

They can exhibit more than one oxidation state when they form compounds

15

Are halogens oxidising or reducing agents?

Oxidising - they gain electrons and so are reduced

16

Which element in a compound is taken as the one with a negative oxidation state?

The most electronegative element

17

Why is the most electronegative element the one with a negative oxidation state?

It has more power to withdraw electron density

18

Oxidation state of an uncombined element?

Zero

19

Oxidation state of a simple ion? Are there any exceptions to this?

Charge on ion - exception in some cases (e.g. halogens, hydrogen, oxygen)

20

Oxidation state of group 1 elements in a compound? Are there any exceptions to this?

+1 - no exceptions

21

Oxidation state of group 2 elements in a compound? Are there any exceptions to this?

+2 - no exceptions

22

Oxidation state of fluorine? Are there any exceptions to this?

-1 - no exceptions

23

Oxidation state of oxygen? Are there any exceptions to this?

-2 - except when in peroxides and combined with F

24

Oxidation state of hydrogen? Are there any exceptions to this?

+1 - except in metal hydrides

25

Oxidation state of chlorine? Are there any exceptions to this?

-1 - except when with O or F

26

What is the sum of oxidation states of all elements in a compound?

Zero

27

What is the sum of the oxidation states of elements in a polyatomic ion equal to?

The charge on the ion

28

Why is oxygen's oxidation number not -2 when combined with F?

F is more electronegative

29

What is the oxidation number of S in H₂SO₄?

+6

30

What can oxidation states be used to determine?

What has been oxidised and reduced in a reaction (therefore oxidising and reducing agents)