Lab

Summary

In this lab, students design and carry out an experiment to explain a reaction between iron and copper(II) chloride.

Grade Level

High school

Objectives

By the end of this lesson, students should be able to

• write balanced chemical equations.
• design and carry out an experiment to answer questions presented to them.
• convert from moles to grams and from grams to moles.

Chemistry Topics

This lesson supports students’ understanding of

• Stoichiometry
• Balanced chemical equations
• Oxidation number

Time

Teacher Preparation: 15 minutes–1 hour

Lesson: two to three 50-minute class periods

Materials

For each group:

• 0.2-M copper(II) chloride solution (up to 100 mL)
• 1-M hydrochloric acid
• Two iron nails
• Balance
• Wash bottles
• Filtering equipment
• Drying oven

Safety

• Always wear safety goggles when working with chemicals in a laboratory setting.
• Excess copper(II) chloride solution must be placed in the waste container in the hood.
• When working with acid, if any solution gets on students’ skin, they should alert you and immediately rinse the area with water.
• Used nails and copper must be placed in the waste beaker in the hood.
• Students should wash their hands thoroughly before leaving the lab.
• When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.

Teacher Notes

This is a very open-ended lab. Depending on time constraints and your students’ previous knowledge, you could spend some time before the lab going over what is expected and provide tips for how to carry out the experiment.

Downloads

• Teacher Guide.doc
• Teacher Guide.pdf
• Student Activity.doc
• Student Activity.pdf
  
  

Submitted by
Mike Staton
Evergreen High School
Vancouver, Washington

For the Student

Lesson

Background

A young mine engineer was walking through a large open pit that is used to mine copper metal to check on a construction project for her miners. She noticed something she thought was strange in some of the mud puddles after a rain storm. She first noticed that the water in many of the puddles was bluish in color. Second, she noticed that there were other puddles that were yellowish in color. The yellowish ones she saw had several nails dropped in them from the construction crew. She also noticed that the nails in these yellowish puddles were covered with rusty orange colored fuzz. She collected several samples as she needed to determine what this was and whether it is safe for the working environment. She sent these samples to your chemical analysis company.

The head chemical engineer has assigned your team the task of creating a lab to answer the mine engineers questions (listed below). He pulled several items from the chemical store room for you team to use; they are also listed below. You must design and carry out an experiment that will produce data to answer the mine engineer’s questions and possibly alleviate her concerns.

Previous knowledge you will need to use:

• How to create and balance a chemical equation
• How to determine the oxidation number of an element

Mine Engineers Questions

1. What is the bluish liquid that was found in some of the puddles?
2. Why was the liquid yellowish in puddles where iron nails were found?
3. Are these two liquids toxic?
4. What is growing on the iron nails that are at the bottom of the yellowish puddles of water?

Available Materials

• 0.2-M copper(II) chloride solution
• 1-M hydrochloric acid     
• Two iron nails
• Balance                
• Wash bottles        
• Filtering equipment
• Drying oven          

Safety and Waste Disposal

• Goggles and Lab Aprons are mandatory. Please wash your hands after handling all chemicals.
• Excess Copper chloride solution must be placed in the waste container in the hood.
• When working with acid, if any solution gets on your skin, alert your teacher and immediately rinse the area with water.
• Used nails and copper must be placed in the waste beaker in the hood.

Activity

• Each lab team must complete the following:
  • A correctly answered set of Prelab Questions: Approved before experimentation
  • Role assignments and a timeline
    • Who is doing what job

• Design an experiment that will solve the miner’s problem. Using the materials listed, carry out the experiment.
• Data analysis must include the following:
  • The number of moles of each compound produced.
  • The number of moles of each compound used.
  • The ratio of moles of one compound to the other.
  • Determine the compound formula and the compound name of the yellowish liquid produced in the reaction.
  • A complete balanced chemical equation of the correct reaction.

• Create a lab report

Prelab Questions

1. Write two balanced chemical equations for the reaction of iron with copper(II) chloride.
   1.  Make one for iron(II) and one for iron(III).
2. Determine how many moles of iron metal are present in 34.0g.
3. What is the mass of one mole of copper?
4. Explain how you will determine the mass of iron lost from the nail during the reaction.

Explain how to determine the theoretical yield mass of copper from the lost mass of iron from the nail.

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