Redox Reactions Review

Oxidation Numbers

100

The oxidation number of any element.

What is zero?

200

The oxidation numbers of the constituent atoms in any polyatomic ions should be equal to this.

What is the charge of the polyatomic ion?

300

The oxidation number of sulfur in the polyatomic sulfate ion, which has a -2 charge. (SO₄^2-).

What is +6?

S + 4(-2) = -2 

400

The oxidation number of Chromium in Na₂Cr₂O₇.

What is +6?

Cr₂O₇^2- --> 2Cr + 7(-2) = -2

2Cr = 14 - 2 = +12    Cr = +6

500

The oxidation number of Carbon in C₄H₈.

4C + 8(1) = 0

4C = -8    

What is C = -2?

Classifying Reactions

100

What kind of reaction is this (besides possibly redox)?

2Ag + S ---> Ag₂S

Also, is it redox?

What is Formation?

Yes, it is redox since there is a change of charge for both Ag and S.

200

Name this reaction (besides possibly redox):

2Al + Fe₂O₃ ---> Al₂O₃ + 2 Fe

Also, is it redox?

What is Single Replacement (Redox)?

Redox because Fe and Al change charge.

300

Name this reaction (besides possibly redox):

CuF₂ + H₂SO₄ ---> CuSO₄ + 2HF

Also, is it redox?

What is Double Replacement (Not Redox))?

400

Name this reaction (besides possibly redox):

2C₆H₆ + 15O₂ ---> 12CO₂ + 6H₂O

What is Combustion (Redox)?

Redox since oxygen goes from 0 to -2 (GER) and carbon goes from -1 to +4 (LEO)

500

Name this reaction (besides possibly redox):

LiOH + HCl ---> LiCl + H₂O

Also, is it redox?

What is Acid-Base (Not Redox)?

Not redox since their is no change of charge.

Reduction, Oxidation & Agents of Redox

100

The oxidizing agent in the following: 2Li + S ---> Li₂S

What is Sulfur?

Li is being oxidized, goes from 0 to +1 (LEO)

Sulfur is reduced (0 to -2) - GER

200

The chemical reduced in the following: 4Fe + 3O₂ ---> 2Fe₂O₃

What is Oxygen?  (0 to -2)  GER

300

The reducing agent in the following, and what is being reduced: 

Mg + 2HCl ---> MgCl₂ + H₂

What is Magnesium?  Hydrogen is reduced, going from +1 to 0  (GER)

400

Which is the oxidizing agent (being reduced itself)?: 

KMnO₄ + HCl ---> MnCl₂ + Cl₂ + H₂O + KCl

Manganese goes from +7 to +2  (GER)  being reduced and the oxidizing agent

500

What kind of agent of redox can water act as?

What is both oxidizing & reducing agent

Spontaneity

100

The type of reaction that oxidizing agents undergo

What is Reduction

200

The Class of elements tend to be good reducing agents

What is Metals

300

You place 3 different metals (Zinc, Iron, Magnesium) into distilled water. Which would you expect to quickly react?

What is Magnesium

400

Which metal in the data booklet is the weakest reducing agent?

What is Gold

500

If we tested 3 different metals (Ag, Cu, Zn). Which metal ion solution would react spontaneously with Copper metal?

What is Silver ions

Redox Terminology

100

What is lost during oxidation?

What are electrons

200

The change in oxidation number during reduction

What is decrease

300

Consider the reaction:   2H⁺_(aq)   ->   H_2(g) 

What side of the reaction would electrons be on?

What is the left side (reactants)

400

When producing iron metal, iron ore undergoes what type of process? (Reduction or oxidation)

What is Reduction

500

Reaction where the same entity undergoes both oxidation and reduction

What is disproportionation