Student Exploration_ Boyle's Law and Charle's Law

Name: Date: 9/18/2023 Student Exploration: Boyle’s Law and Charles’s Law Directions: Follow the instructions in red to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: absolute zero, Boyle’s law, Charles’s law, Gay-Lussac’s law, Kelvin scale, pressure Gizmo Warm-up The Boyle’s Law and Charles’s Law Gizmo shows a container of gas. Inside the container, the small purple spheres represent gas molecules. 1. Observe the particles. Are they all moving at the same speed ? No 2. How do the particles interact with the walls and lid of the container? The particles bounce off the walls and lid of the container. These interactions contribute to the pressure on the walls of the container. Pressure is defined as force per unit area. In the Gizmo, pressure is measured in units of N/m 2 Slowly drag the temperature ( T ) slider back and forth. (Note: In this Gizmo, the Kelvin scale is used to measure temperature. On the Kelvin scale, 0 degrees is absolute zero , the coldest possible temperature. Absolute zero is equal to -273.15 °C or -459.67 °F) 3. A. How does the change in temperature affect the speed of the molecules? The change in temperature affects the pressure of the molecules. B. How does the change in temperature affect the volume of the container? The change in temperature affects how large or how little the volume of the container is. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Activity A: Boyle’s law Get the Gizmo ready: ● Set the temperature ( T ) to 300 K. ● Check that the mass ( m ) is set to 0 kg. Question: How does pressure affect the volume of a gas? 1. Form hypothesis: In this experiment, you will pile weights on the lid of the container of gas. What do you think will happen as more weight is added to the lid? As weight is added, pressure of the molecules will be increased and the volume will decrease. 2. Notice: Look at the DESCRIPTION pane. What is the mass of the lid ? Look in the yellow Gizmo Status box on the right of the simulation. (fill in the blank in the orange box below) How much pressure does the lid exert on the gas? Look in the bottom right of the Gizmo to see the pressure. (fill in the blank in the orange box below) The mass of the lid is 10kg. The pressure exerted by the lid is 98.1N/m2. 3. Collect data : With the temperature held constant at 300 K, use the Select mass slider to place weights on the lid. Record the pressure and volume of the gas for each added mass in the data table below. (Each block is 5 grams. The volume and pressure are found at the bottom right of the Gizmo) Your first pressure and volume data in the chart below will be of the lid only with NO added mass. Added mass on the lid Total mass (lid + added mass) Pressure in N/m 2 Volume in m 3 0 kg (lid only) 10 kg (lid only) 91.1 2.54 10 kg (2 blocks) 20 kg (lid + 2 blocks) 196.2 1.27 20 kg (4 blocks) 30 kg (lid + 4 blocks) 294.3 0.85 30 kg (6 blocks) 40 kg (lid + 6 blocks) 392.4 0.64 4. Analyze: As the pressure increases at constant temperature, what happens to the volume of the gas? When the pressure increases at constant temperature, the volume of the gas decreases. This relationship is called Boyle’s law. 5. Calculate : Compare the pressure and volume values in your data table. A. How did doubling the pressure change the gas volume ? The volume was divided by 2. B. How did tripling the pressure change the gas volume ? The volume was divided by 3. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

6. Apply : A. Based on what you learned, what would happen to a balloon placed in the freezer? The balloon would shrink B. What would happen to a balloon placed in a warm oven? (Assume it doesn’t pop.) The balloon would expand Activity C: Gay-Lussac’s Law Get the Gizmo ready: ● In this order, on the SIMULATION pane: 1. Set T to 300 K. CLICK ENTER KEY 2. Set m ass to 15 kg. CLICK ENTER KEY 3. Click on the “Constant volume” checkbox. (bottom right of Gizmo) 4. Check to see that the volume (bottom right of the Gizmo) is 1.02 m 3 . If not, reset the Gizmo and start back over at Step 1. Question: How does temperature affect the pressure of a gas when volume is constant? 1. Form hypothesis: If the volume of a gas is held constant, how do you think the pressure will change as temperature increases ? The pressure will increase as the temperature increases. 2. Collect data: Select the TABLE tab (Top right of Gizmo). Record the pressure when T = 100 K, 200 K, and so forth up to 500 K . (Note: The volume will remain constant at 1.02 m 3 .) For each temperature, type in the temperature, click ENTER, and then click the RECORD button below the table to get the pressure data. Temperature Pressure in N/m 2 100 K 81.75 200 K 163.5 300 K 245.25 400 K 327 500 K 408.75 3. Analyze: When the volume is held constant, how does the pressure change as temperature increases ? The pressure increases as the temperature increases. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

This relationship is called Gay-Lussac’s law. 4. Explain: Based on the motions of the gas molecules, why do you think the pressure changed as it did when the temperature was increased ? The molecules had more energy therefore there was more movement and as a result, the pressure increased. 5. Calculate: Compare the pressure and temperature values in your data table. A. How did doubling the temperature affect the pressure ? The pressure doubled B. How did tripling the temperature affect the pressure ? The pressure tripled. 6. Apply : Based on what you learned, what do you think would happen if you placed a sealed container of gas into a fire? The sealed container would burst open due to the increase in pressure. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved