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Decomposition of Copper (II) Carbonate Mark as Favorite (1 Favorite)

LAB in Classification of Reactions, Chemical Change, Predicting Products. Last updated July 14, 2024.

Summary

In this lab, students will thermally decompose copper (II) carbonate, then collect the oxides produced in the reaction and combine them with water to create synthesis reactions.

Grade Level

High School

NGSS Alignment

This lab will help prepare your students to meet the performance expectations in the following standards:

  • HS-PS1-2: Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
  • Scientific and Engineering Practices:
    • Analyzing and Interpreting Data
    • Planning and Carrying Out Investigations
    • Engaging in Argument from Evidence
    • Obtaining, Evaluating, and Communicating Information

Objectives

By the end of this lab, students should be able to:

  • Interpret lab data and observations to correctly identify the components of a chemical reaction and write the corresponding chemical equation.
  • Carry out a laboratory procedure to thermally decompose copper (II) carbonate and test for gas production in a chemical reaction.

Chemistry Topics

This lab supports students’ understanding of:

  • Chemical Reactions
  • Chemical Change
  • Indicators of a Chemical Reaction
  • Decomposition Reactions
  • Synthesis reactions
  • Predicting Products of a Chemical Reaction
  • Observations

Time

Teacher Preparation: 15 minutes
Lesson: 45-60 minutes (depending on class size)

Materials (per group)

  • Copper (II) carbonate basic
  • Test tubes (2)
  • Test tube rack
  • Test tube clamp
  • Test tube tongs
  • Bunsen burner
  • Retort stand
  • Graduated cylinder
  • Water
  • pH paper
  • Universal indicator
  • Scale
  • Stoppers #1 size (2)

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • 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.
  • Always use caution around open flames. Keep flames away from flammable substances.
  • Always be aware of an open flame. Do not reach over it, tie back hair, and secure loose clothing.
  • Consult the SDS for Copper (II) Carbonate.

Teacher Notes

  • Teachers should do this lab themselves first to gain a better understanding and anticipate expected results as well as potential problems.
  • Groups of 2-3 students works well for this lab.
  • Students should be familiar with the process of Bunsen burner lighting prior to this lab. If needed review the procedure and be sure to emphasize safety precautions with students.
  • This lab is used to demonstrate a quick and simple decomposition reaction of a metal carbonate which allows students to observe a noticeable color change in the solid and to collect and test for CO2 gas using a burning splint test.
  • This lab should be performed after students have completed lessons on synthesis and decomposition reactions. However, it also requires that students have knowledge of acids, bases, and hydrates.
    • Thermal Decomposition: CuCO3 (s) → CuO(s) + CO2 (g)
  • This experiment also allows for 2 synthesis reactions to occur. Combining the two oxides that are produced with water will produce an oxyacid and a hydroxide base.
    • Oxyacid Synthesis: CO2(g) + H2O (l) → H2CO3 (aq)
    • Hydroxide Synthesis: CuO(s) + H2O (l) → Cu(OH)2 (aq)
  • Some students may not realize that condensation is forming within the test tube (when heating) as they are more preoccupied with the color change of the solid.
  • Copper (II) carbonate basic also contains a hydroxide ion that will be liberated as water during the decomposition. I tell students that the solid is copper (II) carbonate monohydrate (though isn’t completely true), which allows us to observe an extra type of decomposition reaction (of a hydrate). The students will notice that condensation will form on the sides of the test tube. Telling them it is a monohydrate as opposed to ‘basic’ eliminates a lot of confusion and still allows them to properly analyze the reaction.
    • CuCO3. H2O(s) → CuCO3 (s) + H2O (l)

For the Student

Objective

To observe and understand the multiple reactions occurring as we thermally decompose Copper (II) Carbonate Monohydrate.

Prelab Questions

  1. What is produced when a metal oxide reacts with water?
  2. What is produced when a non-metal oxide reacts with water?
  3. What is produced when a hydrate (such as CuSO4.5H2O) is decomposed?
  4. What is produced when a metal carbonate is decomposed?
  5. What are the indicators of a chemical change?

Materials

  • Copper (II) carbonate monohydrate
  • Test tubes (2)
  • Test tube rack
  • Test tube clamp
  • Test tube tongs
  • Bunsen burner
  • Retort stand
  • Graduated cylinder
  • Water
  • pH paper
  • Universal indicator
  • Scale
  • Stoppers #1 size (2)

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • Wash your hands thoroughly before leaving the lab.
  • Follow the teacher’s instructions for cleanup of materials and disposal of chemicals.
  • Always use caution around open flames. Keep flames away from flammable substances.
  • Always be aware of an open flame. Do not reach over it, tie back hair, and secure loose clothing.

Procedure

  1. Label the test tubes A and B.
  2. Obtain the mass of test tube A and record it in the data table. Use the scale to measure approximately 1.00g (±0.05g) of copper (II) carbonate monohydrate into test tube A. Record the exact mass of copper (II) carbonate monohydrate in the data table.
  3. Place test tube A in a test tube clamp. Setup a retort stand with the test tube clamp as shown. Place a Bunsen burner beneath the test tube.
  4. Light the Bunsen burner and heat the solid in test tube A until its color completely changes. Notice what forms on the sides of the test tube while heating. Record your observations in the data table.
  5. While heating the solid, place test tube B at the mouth of test tube A and hold it there for approximately one minute. Use test tube tongs if necessary.
  1. Stopper test tube B and place it in a test tube rack. Turn off the burner when the reaction is complete. Quickly insert a burning splint into the opening of test tube A and record your observations in the data table.
  2. Once test tube A has cooled, determine the mass the test tube with the heated solid. Record the mass in the data table.
  3. Measure approximately 5mL of water in a graduated cylinder and determine the pH of the water using pH paper. Record it in the data table.
  4. Add approximately 2 mL of the water to test tube A. Stopper the test tube and shake to combine. Determine the pH of the solution using both pH paper and 1 drop of Universal indicator.
  5. Next, add approximately 2 mL of water to test tube B. Stopper the test tube and shake to combine. Determine the pH of the solution using both pH paper and 1 drop of Universal indicator.

Data

Substance
Observations before heating
(including mass)
Observations during heating
Observations after heating
(including mass)
Copper (II) Carbonate Monohydrate
(and burning splint result)
Substance
pH value of water
pH value of mixture (pH paper)
pH value of mixture (universal indicator)
Water + test tube A contents after heating
Water + test tube B after heating

Analysis Questions

  1. How did you know that the copper (II) carbonate was fully decomposed? State and explain one quantitative and one qualitative piece of evidence from your data table that indicated this.
  2. Write the thermal decomposition reaction of copper (II) carbonate. Include states.
  3. What did you notice was formed on the sides of the test tube during the heating of the solid? Why did this happen? Write a balanced chemical equation and include states.
  4. What happened to the burning splint when you placed it in the opening of test tube A? Why did this occur?
  5. What type of reactions occurred in steps 9 and 10? Write a balanced equation with states for each. What type of product was made in each reaction? What is your proof?
  6. State one source of error that may have contributed to your results. Why did this error occur, what was its impact and how could you prevent it next time?

Application

In a paragraph form, explain how a fire extinguisher works.
Source all of your work and include information about the following:

  • The purpose of the extinguisher (why and when we use one).
  • The chemicals that are inside of the cylinder (and any relevant reactions).
  • Why the contents of the extinguisher are made of gas.
  • Explanation of how it works to put out a fire.