Question

 

Oxidation-Reduction Activity Series

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Version 42-0186-00-02

Lab Report Assistant

This document is not meant to be a substitute for a formal laboratory report. The Lab Report Assistant is simply a summary of the experiment’s questions, diagrams if needed, and data tables that should be addressed in a formal lab report. The intent is to facilitate students’ writing of lab reports by providing this information in an editable file which can be sent to an instructor.

Exercise 1: Describing an Oxidation-Reduction Reaction

Data Table 1. Redox Reaction of Copper and Silver Nitrate.

Note: Copper has a +2 oxidation number in the products.

Initial observations before beginning	Copper is shiny thin squared metal; silver nitrate is a clear liquid that seems like water.
Observations	The copper began to change color from bright shiny to a dull dark color, almost looked black.
Observations after 30 minutes	The copper formed crystals which look like mold and foam mixed.
Chemical equation	Cu + 2AgNO3 ® Cu(NO3)2 + 2Ag
Element that is oxidized	Cu
Element that is reduced	Ag
Spectator ion	NO3
Oxidizing agent	Ag
Reducing agent	Cu

Questions

Define oxidation, reduction, and oxidation number. Describe how oxidation and reduction affect the oxidation number of an element.

Oxidation is the loss of electrons by a substance undergoing a chemical reaction. During oxidation, the oxidation number of the element increases and becomes more positive. Reduction is gain of electrons by a substance undergoing a chemical reaction. During reduction, the oxidation number of the element decreases and becomes more negative. Oxidation is a number assigned to an element in a compound. The number enables us to describe oxidation –reduction reactions, and balancing chemical reaction. Oxidation number increases when a reactant gets oxidized and when it gets reduced.  

Define oxidizing agent, reducing agent, and spectator ion.

Oxidizing agent: the reactant that accepts electrons and oxidizes another one participating in the reaction. Reducing agent: the reactant that donates electron and reduces another one participating in the section. Spectator ion: the reactant that does not get affected during the reaction.

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

The new substance appears moldy/foamy and small crystals formed. Parts of it are very dark, appearing nearly black and others are very bright and shiny. The new formula is Cu (NO³)²

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 from Data Table 1.

Copper would be more active than silver. Since copper is more active it will likely easily lose electrons to the silver ions that will convert the silver ions into the silver metal. It is also indicated in Data Table 1 as the I observed the solid change into a crystal moldy foam.

Solid copper sulfide and silver nitrate react to form copper (II) nitrate and solid silver sulfide. Write a balanced chemical equation that describes the reaction. Identify 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.

CuS(s) + 2AgNO₃(aq)à Cu(NO₃)₂(aq)+ 2Ag₂S(s)

Oxidation NO- +2 -2         +1          +5 -2                +1 -2         +2 +5 -2

Yes, it is a redox reaction because the electrons are transferred between the copper and silver.

Exercise 2: Creating an Activity Series

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

Solid metal	Well ID	Solution	Immediate observations	30 Minute Observations
Cu	A1	Pb(NO3)2	None	None
	A2	Zn(NO3)2	None	None
Pb	B1	CuSO4	Lead went from shiny with scrapes back to a dark rusted lead color.	The leads surface has become shiny copper colored.
	B2	Zn(NO3)2	none	none
Zn	C1	CuSO4	Copper crystals immediately began to form.	The zinc has been completely engulfed in copper crystals.
	C2	Pb(NO3)2	Lead crystals immediately began to form.	As with the copper, the lead has completely engulfed the zinc piece.

Data Table 3. Potential Redox Reactions and Chemical Equations.

Metal and      Metallic Solution	Reaction Occurred?	Chemical Equation
Cu + Pb(NO3)2	No	same
Cu + Zn(NO3)2	No	same
Pb + CuSO4	Yes	PbSO4 + Cu
Pb + Zn(NO3)2	No	same
Zn + CuSO4	Yes	Cu + ZnSO4
Zn + Pb(NO3)2	Yes	Zn(NO3)2 + Pb

Questions

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.

Element = Pure Form, Compound Form

Copper = 0, +2

Lead = 0, +2

Zinc = 0, +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 from Data Table 3.

Copper is the strongest oxidizing agent because it didn’t act as a reducing agent unlike the silver.

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 from Data Table 3.

Zinc because it didn’t act as a oxidizing agent at all during this lab compared to the other elements.

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

When the metal activity raises/ the higher it is, the more it oxidizes. Highly active metals tend to donate electrons.

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

From top of the list to the bottom

Zn, Pb, Cu

 

Answer 1

Define oxidation, reduction, and oxidation number. Describe how oxidation and reduction affect the oxidation number of an element.

Oxidation is the loss of electrons by a substance undergoing a chemical reaction. During oxidation, the oxidation number of the element increases and becomes more positive. Reduction is gain of electrons by a substance undergoing a chemical reaction. During reduction, the oxidation number of the element decreases and becomes more negative. ** Oxidation is a number net indicative charge of an element in a compound. The number enables us to describe oxidation –reduction reactions, and balancing chemical reaction. Oxidation number increases when a reactant gets oxidized and when it gets reduced.  

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 from Data Table 3.

*Silver is the strongest oxidizing agent because it didn’t act as a reducing agent unlike the copper.

the one which removes electron is oxidizing agent

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 from Data Table 3.

Zinc because it didn’t act as a oxidizing agent at all during this lab compared to the other elements.

correct as zinc will loose electron more easily than other in the list

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

When the metal activity raises/ the higher it is, the more it oxidizes. Highly active metals tend to donate electrons.

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

From top of the list to the bottom

Zn, Pb, Cu