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LAB in Physical Properties, Covalent Bonding, Ionic Bonding. Last updated March 25, 2019.
Summary
In this lab, students will participate in a guided inquiry in which they will test different physical properties, such as conductivity and solubility of given samples. This lab can be used to introduce ionic, covalent and metallic bonds as well as their properties. This lab should help students make connections between the types of bonds, differentiate between them, as well as help to better understand the nomenclature of ionic and covalent compounds.
Grade Level
High School
NGSS Alignment
This lab will help prepare your students to meet the performance expectations in the following standards:
- HS-PS1-1: Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.
- Scientific and Engineering Practices:
- Analyzing and Interpreting Data
Objectives
By the end of this lab, students should be able to
- Identify compounds as ionic, covalent, or metallic based on their chemical formula.
- List some properties of ionic, covalent, and metallic bonds.
Chemistry Topics
This lab supports students’ understanding of
- physical properties
- compounds
- ionic bonds
- covalent bonds
- metallic bonds
Time
Teacher Preparation: 30 minutes
Lesson: 50 minutes (including whole class debrief)
Materials
- well plates (1/group)
- conductivity meter (link to recommended meter)
- toothpicks or stirring rods (10/group)
- pipettes (1/group)
- distilled H2O (~100 mL/class)
- tap H2O (~100 mL/ class)
- approximately 10 g/class of the following items:
- aluminum foil (Al)
- sugar (C12H22O11)
- salt (NaCl)
- wax (C20H42)
- sand (SiO2)
- Ethanol (C2H6O)
- Copper (Cu)
- Calcium chloride (CaCl2)
- Copper (II) sulfate (CuSO4)
- Gatorade
Safety
- Always wear safety goggles when handling chemicals in the lab.
- Students should wash their hands thorughly before leaving the lab.
- When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
- Do not consume lab solutions, even if they’re otherwise edible products.
- Food in the lab should be considered a chemical not for consumption.
Teacher Notes
- At this point they should be familiar with terms such as solutions, mixtures, compounds, and elements.
- This lab is a wonderful introduction to the properties of the different kinds of bonds.
- You may need to demonstrate how to properly use the conductivity meters, stressing the importance of only allowing the nodes to touch the solution.
- I find this lab is most successful in groups of four.
- You will have to guide the students in grouping the different properties after performing the lab.
- You might find it helpful to discuss the results as a class.I usually guide them in creating the groups.Initially, we create “conduct” and “does not conduct” categories.Then, we make groups of “dissolves” and “does not dissolve” categories.Finally, we create subcategories “conducts when dissolved” and “does not conduct when dissolved.”I have included a picture of the final product.
- Once we have created the different categories, I lead them in a discussion about the similarities and differences of properties and chemical formulas. Finally, I introduce the terms: metallic, ionic, and covalent.
- In order to complete this lab in one class period, I give my students 25 minutes to perform the lab experiments.We discuss the lab results and create categories, and the post lab questions are completed as homework.
- For higher levels, you could make them create their own categories.
For the Student
Background
We are beginning to explore the different kinds of bonds present in compounds.In this lab, you will perform several tests on different compounds.After we have performed the tests, we will categorize the different compounds based on their physical properties.
Pre-lab Questions
- What are examples of physical properties of a compound?
- What is the difference between a compound and a mixture?
- Where are the metals and nonmetals located on the periodic table?What are some properties of each?
- Predict whether each substance will conduct electricity. Explain your reasoning behind your decision.Write your predictions on the left side of data table 1.
- Predict whether each substance will dissolve in water. Explain your reasoning behind your decision. Write your predictions on the left side of data table 1.
Objective
Test the conductivity and solubility of different compounds as a solid and in solution. Then categorize these compounds based on their physical properties.
Materials
- Well plate
- Conductivity meter
- 11 toothpicks or stirring rods
- 20 mL deionized or distilled H2O
- 1 Pipette
- Small samples of the following:
- distilled (H2O)
- tap (H2O)
- aluminum foil (Al)
- sugar (C12H22O11)
- salt (NaCl)
- wax (C20H42)
- sand (SiO2)
- Ethanol (C2H6O)
- Copper (Cu)
- Calcium chloride (CaCl2)
- Copper (II) sulfate (CuSO4)
- Gatorade
Safety
- Always wear safety goggles when handling chemicals in the lab.
- When you complete the lab, dump the materials contained in the well plates in the designated container and rinse the well plates.Please place them upside down on your lab tables in order to allow them to dry for the next class period.
- You should wash your hands thoroughly before leaving the lab.
- Do not consume lab solutions, even if they’re otherwise edible products.
- Food in the lab should be considered a chemical not for consumption.
Procedure
- Obtain a well plate, conductivity meter, and 11 toothpicks or a stirring rod.
- Obtain small samples of all of the compounds in your well plates. Make sure you keep them in order, or write down a key, to ensure you know what compounds you are testing throughout the lab.
- Using the conductivity meters, test the conductivity of all of the substances.Only allow the nodes of the conductivity meters to touch the substances. Record your results in data table 1.
- Next you will test the solubility of these substances.Using the pipette, add distilled water to fill the wells of the aluminum foil, sugar, salt, sand, wax, ethanol, copper, Calcium chloride, and Copper (II) sulfate. Using the toothpicks or stirring rods, try to dissolve the compounds.Record your results in data table 1.
- Finally, you will test the conductivity of the substances that dissolved. Only allow the nodes of the conductivity meters to touch the solutions. Record your results in data table 1. Rinse the nodes with distilled water in between each test.
- Dispose of all substances in the proper disposal containers. DO NOT put these substances in the sink. Rinse the well plates and place them upside down on the lab table.
Data
Test Substances | Predictions | Test Results | |||
Conduct? Yes/No | Dissolve? Yes/No | Conduct? Yes/No | Dissolve? Yes/No | Conduct when dissolved? | |
H2O (l), Distilled water | | Yes | | Yes | |
Al (s), Aluminum foil | | | | | |
C12H22O11 (s), Sugar | | | | | |
NaCl (s), Sodium chloride, salt | | | | | |
C20H42 (s), Paraffin wax | | | | | |
SiO2 (s), Silicon dioxide, sand | | | | | |
C2H5OH (l), Ethanol | | | | | |
Cu (s), Copper | | | | | |
CaCl2 (s), Calcium chloride | | | | | |
CuSO4 (s), Copper (II) sulfate | | | | | |
Gatorade | | Yes | | Yes | |
Analysis
- Which substances conduct electricity but do not dissolve in water? What other things do these substances have in common?
- Divide the substance that dissolved in water into two categories: those that conduct electricity once they are dissolved, and those that don’t. Create a chart.
- What do the substances that conduct electricity once they are dissolved have in common?
- What do the substances that do not conduct electricity once they are dissolved have in common? (Don’t include water.)
- Write a statement about the substances that do light up the conductivity meter.
- Write a statement about the substances that do not light up the conductivity meter.
- Predict whether isopropanol, C3H8O (l), will conduct electricity. State your reasoning.
- The sports drink we tested dissolved in water and was a good conductor. Based on this activity, what conclusions can you make about the sports drink?
- If it is dangerous to take a bath with a blow dryer, what must also be true about the water in the bathtub?