2.1.5 Redox Flashcards
1
Q
what are oxidation numbers used for
A
- used to measure the number of electrons that an atom uses to bond with atoms of another element
2
Q
what does a negative oxidation number mean
A
- electron density has been gained
3
Q
what does a positive oxidation number mean
A
- electron density has been lost
4
Q
what is the oxidation number for elements
A
0
5
Q
what is the oxidation number for hydrogen
A
+1
> unless metal hydrides where its -1
6
Q
what is the oxidation state for oxygen
A
- 2
7
Q
what is the oxidation state for fluorine
A
- 1
8
Q
what is the oxidation state for chlorine
A
- 1
> unless bonded to F or O where it has positive values
9
Q
what is the oxidation state for transition metals
A
- charge is in roman numerals
10
Q
what is the sum of oxidation states in a compound
A
- 0
> sum of oxidation states are balances
11
Q
what is the sum of complex ion oxidation state
A
- the charge on ion
12
Q
what are redox reactions
A
- when one substance is oxidised and another is reduced
13
Q
what is reduction
A
- decrease in oxidation number
> electrons are gained
14
Q
what is oxidation
A
- an increase in oxidation number
> electrons are lost
15
Q
how does redox reactions work
A
- substance that is reduced takes electrons from the substance that is oxidised
16
Q
what is disproportionation
A
- a redox reaction in which a species is simultaneously reduced and oxidised to form two different products
17
Q
describe what happens in redox reactions of metals with acids
A
- metal is oxidised, forming positive metal acids
- hydrogen in acid is reduced, forming element hydrogen as a gas
