In this simulation, students will investigate three of the fundamental gas laws, including Boyle’s Law, Charles’ Law and Gay-Lussac’s Law. Students will have the opportunity to visually examine the effect of changing the associated variables of pressure, volume, or temperature in each situation. Also, students will analyze the gas samples at the particle level as well as manipulate quantitative data in each scenario. Finally students will interpret trends in the data by examining the graph associated with each of the gas laws. This lesson accompanies the simulation from the November 2015 issue of Chemistry Solutions.
High or middle school
By the end of this lesson, students should be able to
- Understand that pressure and volume have an indirect relationship, when temperature is held constant, as shown with Boyle’s Law.
- Understand that temperature and volume have a direct relationship, when pressure is held constant, as shown with Charles’ Law.
- Understand that pressure and temperature have a direct relationship, when volume is held constant, as shown with Gay-Lussac’s Law.
- Accurately calculate the final values for volume, pressure or temperature of a gas sample based on a set of given conditions.
- Predict the spatial distribution of particles in the gas sample as variables are changed.
- Describe the interaction and motion of particles in the gas sample as variables are changed.
- Interpret trends in the data by examining the graph associated with each of the gas laws.
This lesson supports students’ understanding of
- Gas Laws
Teacher Preparation: 10 minutes
Lesson: 45–60 minutes
- Computer with internet access
No specific safety considerations are needed for this investigation.
- This simulation is designed so that students can interact with Boyle’s Law, Charles’ Law and Gay-Lussac’s Law separately. Tabs on the top on the screen will allow for selection of the particular law to investigate.
- This simulation is intended for students to practice completing the gas law calculations, as well as to connect specific particle behavior with the associated variable of volume, temperature or pressure.
- In addition, by clicking on the “Add Data” button, students can collect data to create a graph for each of the gas laws.
- Depending on the gas law chosen, the variable that is held constant will not be available to manipulate at any point on that particular screen.
- The arrows that appear near each variable should be clicked on to either increase or decrease the particular variable. The exact values will be displayed at the bottom of the screen in the variable list.
- Note that the Celsius temperature value can be shown on the thermometer, but the kelvin value is used for the calculations. When the Kelvin temperature exceeds 423K, the Celsius thermometer will appear to break, as it exceeds its capacity.
- An Answer Key document is available for teacher reference.
For the Student
In this investigation you will examine three gas laws including Boyle’s Law, Charles’ Law and Gay-Lussac’s Law. You will explore how manipulating the variables of volume (L), pressure (atm) and temperature (K) can affect a sample of gas. The formula for each of the gas laws are:
1. Solve for “x” in the following algebraic equations and report your final answer with the correct number of significant digits:
a. (1.34)(5.46) = (1.76)(x)
b. 4.38 = x
c. 2.25 = 4.85
2. Briefly describe, in your own words the meaning of each of the following variables, and common units of measurement associated with each:
Visit teachchemistry.org/gaslaws. Make sure that you select the “Boyle’s Law” tab to begin; it will be shown in white.
- Which one of the three variables: Pressure, Volume or Temperature cannot be changed in Boyle’s Law? This variable is considered a constant.
- Using the volume control arrows, reduce the volume of the gas to 1.70L.
- In the space below record your observations regarding the behavior of the particles in the gas sample as the volume is reduced. Make certain to discuss collisions in your comments.
- Calculate the new pressure value for the gas, showing all of your work.
- Check your final answer for part b by clicking the calculate button next to P2.
|a. Observations when Volume is reduced||b. Calculation|
|P1V1 = P2V2|
- Press the reset button at the top right of the screen. Using the pressure control arrows, reduce the pressure of the gas to 0.700atm.
- In the space below record your observations regarding the behavior of the particles in the gas sample as the pressure is reduced.
- In the space below calculate the new volume value for the gas.
- Check your final answer for part b by clicking the calculate button next to V2.
|a. Observations when Pressure is reduced||b. Calculation
|P1V1 = P2V2|
- Press the reset button at the top right of the screen.
- Using the pressure control arrows, increase the pressure value to 1.50atm, and fill in the corresponding V2 value in the data table below.
- Press the Add Data button. Using the pressure control arrows, increase the pressure to 2.00atm and fill in the corresponding V3 value in the data table below.
- Repeat step b for pressure values of 2.50atm and 2.90atm.
|P1 = 1.00 atm||P2 = 1.50 atm||P3 = 2.00 atm||P4 = 2.50 atm||P5 = 2.90 atm|
|V1 =||V2 =||V3 =||V4 =||V5 =|
Based on the data collected in the table above, what trend can be observed for volume of a gas when the pressure of the gas is increased?
Direct relationship: A relationship between two variables, where a change in one variable results in the same change in the other variable. For example, if one variable is increased, then the other variable will also increase.
Indirect relationship: A relationship between two variables, where a change in one variable results in the opposite change in the other variable. For example, if one variable is increased, then the other variable will decrease.
- Considering the terms described above, do the variables of pressure and volume have a direct or an indirect relationship in Boyle’s Law? Justify your answer with data.
- Considering what you now know about Boyle’s law, make a prediction based on the following situation: What would happen to the pressure of a gas inside a sealed bottle, if the bottle was squeezed tightly, reducing the volume of the gas by half? Explain your thoughts.