Lesson 1 the meaning of oxidation and reduction

Final Report

Exercise 1

CHEM 182 DL1 Oxidation-Reduction Activity Series

Oxidation is the process of being oxidized. Reduction is when a chemical, during a reaction, gains electrons. The oxidation number is the number of electrons that is either gained or lost by the element. The oxidation and reduction affect the oxidation number of an element is that when an element is oxidized or reduced, the reduction number will either increase or decrease

1. Def ine oxidation, reduction, and oxidation number. Describe how oxidation and reduction af fect the oxidation number of an element.

An oxidizing agent gains electrons and then reduces in the chemical reaction that is going on. The reducing agent is when oxidation occurs when an element loses electrons during a reaction. A spectator ion is both a reactant and a product in a chemical reaction.

2. Def ine oxidizing agent, reducing agent, and spectator ion.

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Data Table 1: Redox Reaction of Copper and Silver Nitrate

The new substance that appeared in the test tube during the reaction of copper and silver nitrate was a silverish metallic looking substance. The chemical formula for the substance would be Cu + 2AgNO3 = Cu(NO3)2 + 2 Ag. (This is if we assume the substance is silver or Ag.)

3. In the reaction of copper and silver nitrate, a new substance appeared in the test tube. Describe the physical appearance of the substance and identif y its chemical formula.

Copper would be listed above silver. The copper reacted more than the silver during the experiment. That is why during the experiment the copper was the element that was oxidized was also the oxidizing agent, whereas, the silver was the element that was reduced and was the reducing agent.

4. Given an activity series in which the most active metals are at the top of the list and the least active metals are at the bottom of the list, would copper be listed above silver or would silver be listed above copper? Support your answer with data f rom Data Table 1.

The chemical equation that describes the reaction is: CuS (s) + 2AgNO3(aq) --> 2Ag2S (s) + Cu(NO3)2 (aq). The oxidation number of each element, in order, are: (+2 -2), (+1 +5 -2), (+1 -2), and (+2 +5 -2). This is a non-redox reaction.

5. Solid copper sulf ide and silver nitrate react to form copper (II) nitrate and solid silver sulf ide. Write a balanced chemical equation that describes the reaction. Identif y the oxidation number of each element in the reaction. (You do not need to include the total contribution of charge.) Is this reaction a redox reaction or a non-redox reaction? Explain your answer.

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Photo 1: Chemical Equation for Redox of Copper and Silver Nitrate. Note: Copper has a +2 oxidation number in the products.Silver has its expected oxidation number on the reactons side.

Initial Observations before Beginning

Observations

Observations after 30 min

Element that is Oxidized

Element that is Reduced

Spectator Ion

Oxidiz ing Agent

Reducing Agent

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Exercise 2

Metals: Cu, Pb, and Zn. Oxidation # - Pure: 0, 0, and 0. Oxidation # - Compound: +2, +2, and +2.

1. List each of the metals tested in Exercise 2. Indicate the oxidation number when each element is pure and the oxidation number when each element is in a compound.

The metal that was the strongest oxidizing agent was copper. I don't think copper is the reducing agent because it is more so the oxidizing agent during the reactions.

2. Which of the metals in Exercise 2 was the strongest oxidizing agent? Was there an instance when this metal also acted as a reducing agent? Explain your answer using data f rom Data Table 3.

The strongest reducing agent was zinc. There weren't any instances when the metal also acted as an oxidizing agent. The oxidization was done more by the copper.

3. Which of the metals in Exercise 2 was the strongest reducing agent? Was there an instance when this metal also acted as an oxidizing agent? Explain your answer using data f rom Data Table 3.

The ease of oxidation correlates with the activity because the more active, the easier it is to oxidize. The highly active metals tend to donate electrons to other metals.

4. How does ease of oxidation correlate with activity? Do highly active metals tend to donate electrons or accept electrons f rom other metals?

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Data Table 2: Redox Reactions of Copper, Lead, and Zinc

The most active metal at the top of the list would be Zn, the second would be Pb, and the third Cu.

5. Create an activity series for copper, lead, and zinc. Place the most active metal at the top of the list.

Solid Metal Well ID

Cu A1

Cu A2

Pb B1

Pb B2

Zn C1

Zn C2

Solid Metal Solution

Cu Pb(NO )

Cu Zn(NO )

Pb CuSO

Pb Zn(NO )

Zn CuSO

Zn Pb(NO )

Solid Metal Immediate Observation

Cu

Cu

Pb

3 2

3 2

4

3 2

4

3 2

The liquid is clear while the copper is bronze in color.

The liquid is clear while the copper is bronze in color.

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Data Table 3: Potential Redox Reactions and Chemical Equations

Pb

Zn

Zn

Solid Metal 30 Minute Observation

Cu

Cu

Pb

Pb

Zn

Zn

There are a few bubbles that form around the lead, which turns bronze in color.

The lead is silver in color.

The z inc turned reddish from the top.

The z inc turns black.

There was no change.

There was no change.

The lead starts to rust.

There was no change.

The z inc was black with a little bit of red on the top.

The z inc becomes dark grey from the top.

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Photo 2: Chemical Equations and Redox Numbers for Reactions

Metal and Metallic Solution Reaction Occurred?

Cu + Pb(NO )

Cu + Zn(NO )

Pb + CuSO

Pb + Zn(NO )

Zn + CuSO

Zn + Pb(NO )

3 2

3 2

4

3 2

4

3 2