Assignment: Model ChemLab experiment: Charles’ Law
Assignment: Model ChemLab experiment: Charles’ Law
Model ChemLab experiment: Charles’ Law CHEM 120 Week 4 iLab
Scenario/Summary
For this week’s lab, you will conduct the following Model ChemLab experiment: Charles’ Law.
The mathematical relationship between the temperature and volume of a gas was described by Jacques Charles in 1787. This law states that the volume of a fixed amount of a gas at a constant pressure is directly proportional to its absolute temperature. This equation is written as V = bT, where V is volume, T is temperature, and b is a proportionality constant.
Experimentally, when the same sample of trapped gas is at a constant pressure, the initial volume (V1) divided by the initial absolute temperature (V2) is equal to the final volume (V2) divided by the final absolute temperature (T2). Thus, V1/T1=V2/T2.
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Assignment: Model ChemLab experiment: Charles’ Law
Given this information, you will use Charles’ law to determine if your experimental results match the expected results.
Deliverables
NOTE – Submit your assignment to the Dropbox, located at the top of this page. For instructions on how to use the Dropbox, read these step-by-step instructions. (See the Syllabus section “Due Dates for Assignments & Exams” for due dates.)
For each lab experiment, you will write a laboratory report. Download the iLab Week 4 Report Template. In your lab report, you should include the information below.
Title Introduction:
The first section of your lab report will be the introduction. In this paragraph(s), you are to provide information to the reader so that he or she can understand the purpose of the experiment.
Purpose:
This is a concise statement about the lab’s objective.
Background:
This is a brief summary of the topic you are investigating. Include any information that would be necessary to understand the stated purpose.
Findings:
State the major results of the lab exercise.
Procedure:
This is the second section of your lab report. This section includes information that the reader would need in order to repeat your experimental procedure. Do not include any observations or results in this section. Some questions that you should ask yourself to complete this section include: What chemicals did I use? What equipment did I use? How much of each chemical did I use? How long did I perform a step within the procedure?
Observations and Results:
This is the third section of your report. In this section, you will communicate what you observed during the experiment. The Results section is typically dominated by calculations, tables, and figures. In your tables, label the axes of any graphs.
Discussion:
This is the fourth section of your report. In this section, you will explain, analyze, and interpret what you observed. You will draw conclusions from what you know. This is also where you show the reader that you understand the significance or meaning of the results.
Assignment: Model ChemLab experiment: Charles’ Law
Conclusion:
This is the last section of your report and is separate from the Discussion section. In a few sentences, provide a concluding statement about the results of your laboratory. In a scientific publication, this section summarizes the significant aspects and results and identifies implications for future study.
Required Software
Model ChemLab v 2.4
Access the software at https://lab.devry.edu. Steps: All
Grading Rubric
| Category | Points | Description |
| Introduction | 5 | The background material is complete.Does the description set the stage for the reader? |
| Procedure | 5 | The lab report follows correct and complete procedures. |
| Observations and Results | 5 | Were the results accurate? Were all results included? |
| Discussion | 5 | Was an interpretation of the results included? |
| Conclusion | 5 | Was a concluding statement included? |
| Writing Quality | 5 | The lab report contains correct grammar, spelling, originality, completeness, and so forth. |
| Total | 30 |
A laboratory report will meet or exceed all of the above requirements.
Lab Steps
STEP 1: Access Model ChemLab Software
Log into the lab software by clicking the Connect to the iLab Here link, provided at the top of this page. Follow the information to log into the lab environment that can be found in the iLab section under Course Home.
Select Model ChemLab v 2.4. Once the application loads, select the Charles’ Law Lab and click OK.
For an overview of the Model ChemLab software, and navigation within the program, view the following orientation tutorial:
Tutorial
Cell StructureModel ChemLab Tutorial This tutorial gives an overview of the Model ChemLab software and navigates within the program. Duration: 01:31 minutes
STEP 2: Conduct Experiment
Procedure:
You will conduct five different trials. Temperature conditions will change for each trial. You will use the same setup of the equipment through all five trials.
Initial Setup:
From the Equipment menu, select Gas Syringe Sealed (do not select Gas Syringe with Gauge).
Set Syringe volume to 20ML in the dialog box. Click OK.
Note the barometric reading (air pressure). Right-click on Gas Syringe, and select Thermometer.
Trial A: Record the volume and temperature in the Observations section of your Lab Report template. Note: These values are your V1 and T1, respectively.
Trial B: From the Equipment menu, select a 250 ml beaker. Right-click on the beaker, and select Distilled Water. Add 200 ml of ice water (-20° Celsius). Click OK. Right-click on the beaker, and add Thermometer.
Select the syringe and place it in the beaker. Select the syringe and beaker. Right-click on it, and select Combine (do not select Group).
Allow for the temperature in the syringe to reach the same temperature as the ice water bath (-20° Celsius). This may take three minutes or more.
Assignment: Model ChemLab experiment: Charles’ Law
Record the volume and temperature in the Observations section of your Lab Report Template.
Note: To read the volume of the gas in the syringe, look very closely at the bottom of the syringe’s orange plunger.
Trial C: Remove the syringe from the water bath by right-clicking on it and selecting Remove.
Empty the beaker by right-clicking on it and selecting Empty.
Right-click on Beaker, and add Thermometer.
Right-click on the beaker, and select Distilled Water. Add 100 ml of ice water (-20° Celsius).
Right-click on the beaker, and select Distilled Water. Add 100 ml of room temperature water (20° Celsius) by selecting final volume level of 200 ml. Click OK.
Record the temperature.
Select the syringe, and place it in the beaker. Select the syringe and beaker. Right-click on it, and select Combine (do not select Group).
Allow for the temperature in the syringe to reach the same temperature as the water in the beaker. This may take 3 minutes or more.
Record the volume and temperature in the Observations section of your Lab Report template.
Trial D: Remove the syringe from the water bath by right-clicking and selecting Remove.
Empty the beaker by right-clicking on it and selecting Empty.
Right-click on Beaker, and add Thermometer.
Right click on Beaker, and select Distilled Water. Add 100 ml of room temperature water (20° Celsius).
From the Equipment menu, select Bunsen Burner. Place the Bunsen burner beneath the beaker of water.
Heat until the water reaches 100° Celsius.
Right-click on beaker, and select Distilled Water. Add 100 ml of room temperature water (20° Celsius) by selecting final volume level of 200 ml. Click OK.
Remove the Bunsen burner.
Select the syringe, and place it in the beaker. Select the syringe and beaker. Right-click and select Combine (do not select Group).
Allow for the temperature in the syringe to reach the same temperature as the water in the beaker. This may take 3 minutes or more.
Record the volume and temperature in the Observations section of your Lab Report Template.
Trial E: Remove the syringe from the water bath by right-clicking and selecting Remove.
Empty the beaker by right-clicking on it and selecting Empty.
Right-click on Beaker, and add Thermometer.
Right-click on the beaker, and select Distilled Water. Add 200 ml of room temperature water (20° Celsius).
From the Equipment menu, select Bunsen Burner. Place the Bunsen burner beneath the beaker of water.
Heat until the water reaches 100° Celsius. Remove the Bunsen burner. Select the syringe and place it in the beaker. Select the syringe and beaker. Right-click on it, and select Combine (do not select Group).
Allow for the temperature in the syringe to reach the same temperature as the water in the beaker. This may take 3 minutes or more.
Record the volume and temperature in the Observations section of your Lab Report template.
Assignment: Model ChemLab experiment: Charles’ Law
STEP 3: Write Lab Report
Follow the directions above to write your lab report. Use the Lab Report template that is provided above.
In the Observations and Results section, calculate and record the expected volume (V2) for measured temperature in Trials B, C, D, and E, based upon Charles’ law.
Using Charles’ law, calculate the predicted volume of gas for each of the temperature points in your experiment.
The values from Trial A are your V1 and T1.
The temperature measured in Trials B, C, D, and E is the T2 for that experiment.
You will need to convert °Celsius to °Kelvin (Refer to Chapter 1).
Include the following information in the Discussion section.
Discuss how your calculated values compare to your experimental values.
Discuss how volume changes when temperature changes.
In an actual laboratory, what types of safety precautions are needed?
