Stage 1 Chemistry > Redox > Flashcards

Redox Flashcards

(59 cards)

Study These Flashcards
1
Q

Give three examples of redox reactions in real life.

A

Metal production, combustion reaction, batteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a REDOX reaction?

A

REDOX reactions involve electron exchange, oxidation and reduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is oxidation?

A

Oxidation is the gain of oxygen, loss of hydrogen, increase in oxidation number, the loss of electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is reduction?

A

Reduction is the loss of oxygen, gain of hydrogen, decrease in oxidation number, gain of electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is OIL?
What is LEO?

A

Oxidation is Loss of Electrons.
Loss of Electrons is Oxidation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a reductant or a reducer?

A

A reductant/ reducer is a substance that CAUSES REDUCTION, and OXIDISED, which loses electrons easily.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Can oxidation happen alone?

A

No. Oxidation is always with reduction. Because if there is no reduction, no gain of electrons, no oxidation will happen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is RIG?
What is GER?

A

Reduction is Gain.
Gain of Electrons is Reduction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an oxidant/ oxidiser?

A

An oxidant is a substance that CAUSES OXIDATION, and is easily REDUCED.

Because it gain electrons easily, it causes oxidation of another substance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which element is oxidised and which is reduced?
Fe(s) + Cu2+(aq) -> Fe2+ +Cu

A

Fe lose electrons and is oxidised.
Cu gain electrons and is reduced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How battery works in terms of REDOX reactions?

A

Lithium loses electrons easily, transforming chemical energy to electrical energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe redox in terms oof electron exchange.

A

REDOX reactions involve electron exchange. Reduction is the gain of electrons, whereas oxidation is the gain of electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which substance is being reduced?
Which substance is being oxidised?
Which substance is the oxidant?
Which substance is the reductant?

Zn(s) + Cu2+(aq) -> Cu(s) + Zn2+(aq)

A

Copper is being reduced.
Zinc is being oxidised.
Copper is the oxidant.
Zinc is the reductant.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the steps for balancing redox equations?

A
  1. Write down the redox pairs.
  2. Balance the elements quantity.
  3. Balance the oxygen atoms by adding water molecules (H2O) to the opposite side.
  4. Balance the hydrogen atoms by adding hydrogen ions (protons).
  5. Balance the charges by using the appropriate number of electrons.
  6. Balance charges. (e.g. multiplication)
  7. Add the 2 half-reactions together.
  8. Check for atoms quantities and charges.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Half equation of MnO4- to Mn2+ reduction.

A

MnO4- +8H+ +5e-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Half equation of Cr2O72- to Cr3+.

A

14H+ +6e-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is oxidation number?

A

Oxidation numbers is a way of classifying elements based on how many electrons are lost, gained, or shared with other atoms in a polytomic compounds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the oxidation number of (neutral) atoms and molecules?

F(2), F

A

Zero.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the oxidation number of a monatomic ion? F-

A

The charge of that ion.
Floiride ion =-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the sum of the oxidation number of neutral molecules? H2O

A

Zero.
2H+ + O2- = 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the oxidation number of fluorine within compounds?

A

-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is oxygen’s oxidation number in compounds? What are the exceptions?

A

-2.
Except in the presence of fluorine, fluorine’s oxidation number takes precedence.

Except in oxygen-oxygen bonds, including peroxide (O22-) and superoxide (O2-), where oxygen must neutralise the other’s charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Group 1 ions’ oxidation number within compounds. Na

A

+1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Group 2 ions’ oxidation number within compounds. Mg

25
Hydrogen's oxidation number with C, N, O, F, S, Cl, Se, Br (electronegative elements) compounds. With all other elements?
+1, -1.
26
The oxidation number of H in H2SO4 is
+1
27
The oxidation number of Cr in Cr2O72- is
+6
28
What is the oxidation number of a polyatomic ion? Cr2O7 2-
The charge of that ion. -2
29
What does the change in oxidation represent?
It represents the element has been oxidised or reduced in a redox reaction.
30
If the oxidation number of an element increases, the element has been ...
Oxidised.
31
If the oxidation number of an element decreases, the element has been ...
Reduced
32
What is the oxidatoin number of Te in TeO32-? Is it oxidised or reduced?
+4 From 0-> +4, oxidised.
33
If something is oxidised, does the oxidation number go up or down? is it a reducer or a oxidant?
Oxidation number goes up and it is a reducer.
34
What is an electrochemical cell?
When a more reactive metal is oxidised to produce ions of that metal. The electrons produced are used to reduce another substance and pass through an external circuit to power devices.
35
What is the purpose of salt bridge in electronchemical cells?
To allow ions to move and balance charge.
36
What is the charge of anode and cathode in an electrochemical cell?
anode - negative cathode - positive in an electrochemical cell.
37
Does oxidation occur on the anode/ cathode side?
Anode - oxidation
38
Does reduction occur on the anode/ cathode side?
Cathode - reduction
39
If a substance in anode is oxidised, what will happen to the mass?
It will reduce.
39
Why the negative charged element from the salt bridge goes to the anode side of the electrochemical cell?
The anode side produces more positive ions becuase of oxidation (loss of eletrons), causing many positive ions to flow around. It needs more negative ions to balance the positive ions charge, in order to have enough electrons to repel one another to move the circuit.
40
What is an electrolytic cell?
Energy is put into the circuit to push the electron in the non-spontaneous REDOX direction.
41
Why anode in electrolytic cell is positive?
Because it is connected to the positive terminal of an external power source.
42
Substances that would usually oxidise, would ... in electrolytic cell?
reduce
43
What can electrolytic cell be used for?
To plate metal (to coat a surface with a thin layer of another metal) and produce active metals from their ions. To refine metals, such as copper, zinc and aluminium
44
Why the charge of electrodes in electrolytic cell changes?
It is because energy is put into the circuit to FORCE the electron in the non-spontaneous direction.
45
Why the electrolyte has to be a molten substance, but not a aqueous solution in electrolysis ?
Because water will be reduced rather than the metal as it requires less energy to be reduced. Using a molten substance prevents unexpected products.
46
The ... reactive metal give off their electrons easily.
more
46
The ... reactive metal are easily reduced.
less
47
Metal/ion The more active metal oxidises to its ..., and the less active metal ... are reduced to the ...
The more active metal oxidises to its ions, and the less active metal ion are reduced to the metal.
48
Would anything happen if an iron nail is submeraged in a zinc nitrate solution?
No, because the more active metal's ions are in contact with a less active metal.
49
Under what condition a reaction would occur?
Reaction occurs when a more reactive metal is solid and is put into a less reactive metal solution.
50
What happens when a metal reacts with water?
Hydrogen gas will be released and a hydroxide will be produced. Only the most reactive metals will do this.
51
Na +H2O
NaOH + H2 2Na+2H2O2
52
What is the difference in speed between a more reactive metal and a less reactive metal?
The more reactive metal react faster, whereas a less reactive metal reacts slower.
53
Acids+ Metal = Mg+HCl
Salt and hydrogen gas Mg+2HCl -> MgCl2 + H2
54
Why unreactive elements like copper can be found as a metal rather than a mineral?
It is because unreactive metals don't oxidise easily and don't react with other elements or compounds in the environment.
55
N N3- NO2- NO3-
Nitrogen Nitride Nitrite Nitrate
56
P P3- PO3 3- PO43-
Phosphorus Phosphide Phosphite Phosphate
57
S S2- SO32- SO42-
Sulfer Sulfide Sulfite Sulfate
Stage 1 Chemistry
flashcards
Decks in class (3)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions