Materials Boyle s Law Computer Activity Worksheet Charles Law Computer Activity Worksheet Computer with internet access

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1 Topic: Ideal Gas Law Rachel Battaglia Ideal Gas Law Inquiry Lesson Abstract: This is the first lesson covering the Ideal Gas Law in the Kinetic Molecular Theory unit. This inquiry lesson focuses on students being able to discover for themselves what the ideal gas law states. State Objectives C2.2c Explain changes in pressure, volume, and temperature for gases using the kinetic molecular model. Inquiry objectives Identify patterns in data and relate them to theoretical models. Describe a reason for a given conclusion using evidence from an investigation Big Idea - Pressure is the amount of force that impacts the walls of a container, room or area. A change in pressure results from a volume change. Volume is the area of space that a solid, liquid or gas takes up. A change in volume results from a change in pressure and temperature. Temperature is the amount of internal kinetic energy. Students Prior Knowledge Students know the definitions of temperature, pressure and volume. Students might think that these different elements do not affect each other. They will learn how changing one affects another. Observations/examples/data Boyle Law/ Charles Law IDEAL GAS LAW pv = nrt Students will do a lab based on the ideal gas law. They will record their measurements. Materials Boyle s Law Computer Activity Worksheet Charles Law Computer Activity Worksheet Computer with internet access Activities DAY 1 Introduction (4 minutes) Engage How does the pressure and temperature changes at the Equator affect the changes in season?

2 Main Teaching Activities Question (1 minute) - How does individual changes in temperature, volume, and pressure affect the other two? Students will be thinking about this when doing the lab. They are not meant to answer this at the beginning of the lab. Data/Patterns (30 minutes) - Students will work in pairs to complete the Charles Law experiment. They will fill in charts that show the temperature vs volume relationship, The parts of the worksheets they receive will be up to and including the charts Student Explanations (10-15 mintues) From the data the students collected they will create a graph that shows the correlations between temperature/volume relationships They will have to formulate an explanation of the data based on the measurement changes. Communication (5-10 minutes) - They will present the laws they created from the experiment. DAY 2 Main Teaching Activity Data/Patterns (30 mins) - Today they will jump right into the Boyle s Law Experiment. They will fill in the charts that show the pressure vs volume relationship while temperature is constant. They will receive the parts of the work sheet with the charts they need to fill in. Student Explanations.(10-15 minutes) - From the data students collected they will have to create a graph that show the correlations between pressure/volume relationships. They will have to formulate an explanation of the data based on the measurement changes. Communication (5-10 minutes) - They will also present the law they created from the experiment. DAY 3 Communication (15 minutes) students will explain how the two laws correlate to each other. Scientific Explanations (30 minutes) As a class we will look at Charles and Boyles laws in relation to the idea gas law. We will go over mathematical examples of the laws.

3 Charles Law V1T2 = V2T2 Boyles Law- P1V1 = P2V2 Ideal Gas Law pv = nrt Conclusion Students will answer the question posed from the beginning of the Lesson on Day 1. Student will do the rest of the works sheets for homework. Works cited Kwasny, Michael. "Boyle's Law Lab - PhET Contribution." PhET: Free Online Physics, Chemistry, Biology, Earth Science and Math Simulations. University of Colorado, 10 Apr Web. 01 Apr < Kwasny, Michael. "Charles's Law Lab - PhET Contribution." PhET: Free Online Physics, Chemistry, Biology, Earth Science and Math Simulations. University of Colorado, 9 Apr Web. 01 Apr < Lab Work sheets taken directly from works cited web pages Chemistry Gas Laws Name Period Date Boyle s Law Computer Activity Follow instructions from your teacher to access and open the Gas Properties Simulation. Or you can go to and find the simulation link in the Chemistry simulations. Open the simulation. Click on the Measurement Tools button. Click on the Ruler. This will cause a ruler to appear. The rulers units are in nanometers (nm) but we are going to use the ruler to give us an estimated measurement of volume. You will use the ruler to measure the width of the box. We will then change the units of measurement to liters. For example: initially the box should have a width of 6.6 nm which will be recorded in your data table as 6.6 L (liters). When you are asked to change/measure the volume of the box, use the ruler to do so.

4 What are the graduations on the ruler? (How much is each notch worth?) First, you need to add a gas to your container. Click on the handle of the pump, and add ONE PUMPFUL of gas to your container. Locate the Gas in Chamber data on the right. How many gas particles did you add to your container? What type of gas did you add? Describe the motion of the particles: Boyle s Law looks at the relationship between volume and pressure when there is a constant temperature. You must set your container to constant temperature. Click on the Temperature button in the Constant Perameters on the upper right corner. This will cause the temperature to automatically adjust to whatever the initial value is set at. Set your temperature to constant. What is the temperature of your box? You are going to adjust the volume of the container by clicking on the handle on the left side of the container and dragging it to various widths. Dramatically change the volume of the container to a smaller size. Initially, what happens to the temperature of the box? What does the simulation automatically do to your container to achieve constant temperature? Change the gas to 100 molecules of the HEAVY species by manually setting this in the right box. According to the Kinetic Molecular Theory, what action causes pressure on the inside of the container?

5 Hypothesize: If you will make the container smaller, how will this affect the answer to the previous question? If you make it larger?

6 Fill in the following chart by selecting various Volumes. Measure the volume of the container using the ruler. Calculate the values as indicated in the other columns. Trials Volume (V) Pressure (P) Calculate k1 = (PxV) Calculate k2 = Trial Which variable did you control (independent)? Which variable is the dependent variable? Graph Pressure vs. Volume in the following graph. Use proper scaling. Label the graph appropriately. Draw a curved line best connecting all of the points.

7 Looking at your data and graph, describe the relationship between volume and pressure. As the volume gets larger, what happens to the pressure of the gas? Which value remains consistent in the data table? k1 or k2 This k- value is constant; the ratio between volume and temperature of any point on the graph will be the same. Pick any two points from the graph or table: Point #1 Point #2 V1 = V2 = P1 = P2 = Show the k- value calculation: Write an equation for Boyles s Law: We can use this formula to predict the pressure (P2) or volume (V2) of any gas. Use this formula to complete the following calculations. Show your work. 1. If a gas has a volume of 1.25 L and a pressure of 1.75 atm, what will the pressure be if the volume is changed to 3.15 L? 2. If a gas has a volume of 3.67 L and a pressure of 790 mm Hg, what will the pressure be if the volume is compressed to 2.12 L? What is the pressure in atmospheres (atm)? Convert pressure units. 3. A container has a volume of 5.85 L and a pressure of 4.25 atm. What will the volume be if the container s pressure is changed to 2.75 atm?

8 4. A container has a volume of 2.79 L and a pressure of 5.97 atm. If the pressure changes to 1460 mm Hg, what is the container s new volume? Convert pressure units. Chemistry Gas Laws Name Period Date Charles s Law Computer Activity Follow instructions from your teacher to access and open the Gas Properties Simulation. Or you can go to and find the simulation link in the Chemistry simulations. Open the simulation. Click on the Measurement Tools button. Click on the Ruler. This will cause a ruler to appear. The rulers units are in nanometers (nm) but we are going to use the ruler to give us an estimated measurement of volume. You will use the ruler to measure the width of the box. We will then change the units of measurement to liters. For example: initially the box should have a width of 6.6 nm which will be recorded in your data table as 6.6 L (liters). When you are asked to change/measure the volume of the box, use the ruler to do so. What are the graduations on the ruler? (How much is each notch worth?) First, you need to add a gas to your container. Click on the handle of the pump, and add ONE PUMPFUL of gas to your container. Locate the Gas in Chamber data on the right. How many gas particles did you add to your container? What type of gas did you add?

9 Describe the motion of the particles: You can manually set the number of particles in the chamber by typing in a number in the Gas in Chamber boxes. Change your gas from heavy species to 100 light species. How does the motion of the light gas compare to heavy gas? Change the gas to 100 molecules of the HEAVY species. Charles s Law looks at the relationship between temperature and volume at a constant pressure. You must set your container to constant pressure. Click on the Pressure button in the Constant Perameters on the upper right corner. This should lock your pressure at a constant value (it might fluctuate a very small amount). What is the pressure of your container? As soon as you set the pressure to constant, what happens to the little man next to the box? This little robot is responsible for changing the volume of the container. His position will fluctuate. When you are trying to measure the volume of the container, you must estimate the best average position and record this value. You are going to adjust the temperature of the container by adding or removing heat using the Heat Control under the box. The temperature is found above the box. What units is temperature in? Using your book or the internet, determine the relationship between Kelvin and Celsius.

10 Fill in the following chart by selecting various temperatures. (For example 150 K, 300 K, 600 K, etc.). Measure the volume of the container using the ruler. Calculate the values as indicated in the other columns. Trials Temperature (T) Volume (V) Calculate k1 = (VxT) Calculate k2 = Trial K Which variable did you control (independent)? Which variable is the dependent variable? Graph Volume vs. Temperature in the following graph. Use proper scaling. Label the graph appropriately. Graph the line of best fit.

11 Looking at your data and graph, describe the relationship between temperature and volume. As the temperature gets colder and approaches 0 Kelvin, what happens to the volume of the gas? Which value remains consistent in the data table? k1 or k2 This k- value is constant; the ratio between volume and temperature of any point on the graph will be the same. Pick any two points from the graph or table: Do the calculation: Point #1 Point #2 V1 = V2 = T1 = T2 = Since both fractions equal k, then we can conclude that: This is Charles s Law. We can use this formula to predict the volume (V2) or temperature (T2) of any gas. Use this formula to complete the following calculations. 1. If a gas has a volume of 1.25 L at a temperature of 300 K, what will the volume change to if the container is cooled to 200 K? 2. If a gas has a volume of 3.67 L at the temperature of 500 K, what will the volume change to if the container is heated to 900 K?

12 3. A balloon bought in a store where the temperature is 22 C has a volume of about 3.12 L. The person takes the balloon outside on a hot day of a temperature is 37 C. What is the new volume of the balloon? Becareful of the Temp Units!!! 4. If you did buy a 2.75 L balloon that had a temperature of 295 K, what temperature would you have to heat the balloon to in order to increase the volume to 5.00 L? What is this in Celsius?