Lesson test: Oxidation and reduction

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Oxidation and reduction

1.[2p]
What is the oxidation number of manganese in $Mn$ ?

CorrectNot quite: 7

2.[2p]
What is the oxidation number of oxygen in $O$ ?

CorrectNot quite: 2

3.[3p]
Why is the oxidation number of iron in $F$ given as $+ 8 / 3$ ?

It is an average over two iron(III) and one iron(II) in the real lattice

Correct

Iron can carry a fractional charge

The answer is: It is an average over two iron(III) and one iron(II) in the real lattice

The formula is written incorrectly

The answer is: It is an average over two iron(III) and one iron(II) in the real lattice

Oxygen is $- 8 / 3$ in this compound

The answer is: It is an average over two iron(III) and one iron(II) in the real lattice

4.[2p]
In $Mn + 5 F + 8 \to M + 5 F + 4 O$ , how many electrons does each permanganate ion accept?

CorrectNot quite: 5

5.[3p]
$25.00$ mL of iron(II) solution needs $22.45$ mL of $0.02000$ mol dm⁻³ permanganate. What is the iron(II) concentration in mol dm⁻³?

CorrectNot quite: 0.0898

6.[1p]
The oxidising agent in a redox reaction is the species that is itself reduced.

True

Correct

False

The answer is: True

7.[2p]
Why does a permanganate titration need no indicator?

Permanganate is deep purple and its product is nearly colourless, so the first excess drop colours the flask

Correct

Permanganate reacts with starch

The answer is: Permanganate is deep purple and its product is nearly colourless, so the first excess drop colours the flask

The end point is detected by a temperature change

The answer is: Permanganate is deep purple and its product is nearly colourless, so the first excess drop colours the flask

Permanganate is a primary standard

The answer is: Permanganate is deep purple and its product is nearly colourless, so the first excess drop colours the flask

8.[2p]
$C + 2 O \to C + Cl + O$ . What is this called?

Disproportionation

Correct

Comproportionation

The answer is: Disproportionation

Neutralisation

The answer is: Disproportionation

Precipitation

The answer is: Disproportionation

9.[3p]
Match each species to the oxidation number of the highlighted element.

Sulfur in H2SO4
Chromium in Cr2O7 2-
Nitrogen in NH4+
Oxygen in H2O2

+6
+6
-1
-3

Show the answer

Sulfur in H2SO4: +6 Chromium in Cr2O7 2-: +6 Nitrogen in NH4+: -3 Oxygen in H2O2: -1

1.[2p] What is the oxidation number of manganese in Mn?

2.[2p] What is the oxidation number of oxygen in O?

3.[3p] Why is the oxidation number of iron in F given as +8/3?

4.[2p] In Mn+5F+8→M+5F+4O, how many electrons does each permanganate ion accept?

5.[3p] 25.00 mL of iron(II) solution needs 22.45 mL of 0.02000 mol dm⁻³ permanganate. What is the iron(II) concentration in mol dm⁻³?

6.[1p] The oxidising agent in a redox reaction is the species that is itself reduced.

7.[2p] Why does a permanganate titration need no indicator?

8.[2p] C+2O→C+Cl+O. What is this called?

9.[3p] Match each species to the oxidation number of the highlighted element.

1.[2p]
What is the oxidation number of manganese in $Mn$ ?

2.[2p]
What is the oxidation number of oxygen in $O$ ?

3.[3p]
Why is the oxidation number of iron in $F$ given as $+ 8 / 3$ ?

4.[2p]
In $Mn + 5 F + 8 \to M + 5 F + 4 O$ , how many electrons does each permanganate ion accept?

5.[3p]
$25.00$ mL of iron(II) solution needs $22.45$ mL of $0.02000$ mol dm⁻³ permanganate. What is the iron(II) concentration in mol dm⁻³?

6.[1p]
The oxidising agent in a redox reaction is the species that is itself reduced.

7.[2p]
Why does a permanganate titration need no indicator?

8.[2p]
$C + 2 O \to C + Cl + O$ . What is this called?

9.[3p]
Match each species to the oxidation number of the highlighted element.