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Ideal Gas Laws Student Exploration, Lab Reports of Chemistry

Gizmos Ideal Gas Law Student Exploration Lab worksheets

Typology: Lab Reports

2019/2020

Uploaded on 01/19/2022

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Name:
Date:
Student Exploration: Ideal Gas Law
Directions: Follow the instructions to go through the simulation. Respond to the questions and
prompts in the orange boxes.
Vocabulary: atmosphere, Avogadros law, Boyles law, Charless law, dependent variable, directly proportional,
Gay-Lussacs law, ideal gas, ideal gas constant, ideal gas law, independent variable, inversely proportional,
Kelvin temperature scale, kilopascal, mole, pressure, proportionality, STP, volume
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. Why is it often necessary to add air to your car tires during the winter?
Tires get flatter faster in the cold.
2. Why do you think it might be a bad idea to throw an aerosol can into a fire?
The fire will cause the temperature of the can to rise which makes the pressure rise which will
eventually cause the can to explode.
Gizmo Warm-up
The Ideal Gas Law Gizmo shows molecules moving within a chamber fitted with
a movable piston. As the piston moves up and down, the volume of the chamber
changes. Since gases expand to fill their container, any changes in the volume of
the chamber changes the volume of the gas within.
1. Next to Dependent variable, check that Volume is selected. Using the green
slider, change the pressure. Note what happens to the temperature, volume,
and amount of gas.
What changes?
Volume
What stays the same?
Temperature and moles
2. Using the purple slider on the tank of gas, adjust the number of moles, or amount of gas.
What changes?
Volume
What stays the same?
Temperature and pressure
3. Now make Pressure the dependent variable. Use the red slider to change the temperature.
What changes?
Pressure
What stays the same?
Volume and moles
Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning All rights reserved
This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:00
https://www.coursehero.com/file/89728315/Copy-of-IdealGasLawSEpdf/
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Name: Date:

Student Exploration: Ideal Gas Law

Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary : atmosphere, Avogadro’s law, Boyle’s law, Charles’s law, dependent variable, directly proportional, Gay-Lussac’s law, ideal gas, ideal gas constant, ideal gas law, independent variable, inversely proportional, Kelvin temperature scale, kilopascal, mole, pressure, proportionality, STP, volume Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

  1. Why is it often necessary to add air to your car tires during the winter? Tires get flatter faster in the cold. 2. Why do you think it might be a bad idea to throw an aerosol can into a fire? The fire will cause the temperature of the can to rise which makes the pressure rise which will eventually cause the can to explode. Gizmo Warm-up The Ideal Gas Law Gizmo shows molecules moving within a chamber fitted with a movable piston. As the piston moves up and down, the volume of the chamber changes. Since gases expand to fill their container, any changes in the volume of the chamber changes the volume of the gas within.
  2. Next to Dependent variable , check that Volume is selected. Using the green slider, change the pressure. Note what happens to the temperature, volume, and amount of gas. What changes? Volume What stays the same? Temperature and moles
  3. Using the purple slider on the tank of gas, adjust the number of moles , or amount of gas. What changes? Volume What stays the same? Temperature and pressure
  4. Now make Pressure the dependent variable. Use the red slider to change the temperature. What changes? Pressure What stays the same? Volume and moles Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:

Activity A: Volume relationships Get the Gizmo ready: ● Select Volume as the dependent variable. ● Set Pressure ( P ) to 1.0 atm, Moles ( n ) to 1.0, and Temperature ( T ) to 100 K. Introduction: The dependent variable changes in response to a change in the independent variable in an experiment. Independent variables are controlled by the experimenter and are manipulated to see what effect they might have on the dependent variable. Question: What are some factors that affect the volume of a gas?

  1. Investigate: In this Gizmo, all temperatures are measured using the Kelvin temperature scale. This scale is based directly on molecular motion, with 0 K equal to –273 °C. A. What do you think will happen to the speed of the molecules if a gas is heated? I think the speed of the molecules will increase if the gas is heated B. What do you think will happen to the space between molecules, and thus the volume of a gas, as it is heated? Temperature affects volume so the rising temperature would cause the space between molecules to expand which would lead to a higher volume of gas and the molecules would have more room to move around.
  2. Analyze: Select the TABLE tab to see your data. With temperature set at 100 K, press Record. Increase the temperature in 50 K increments, pressing Record each time. A. What trend do you see? The moles and pressure stay the same but as the temperature goes up so does the volume. B. If the temperature of a gas is doubled, its volume will double C. If the temperature of a gas is halved, its volume will be halved If two variables are directly proportional , an increase in the independent variable will cause the dependent variable to increase at the same rate. If the variables are inversely proportional , an increase in the independent variable will cause the dependent variable to decrease at the same rate. D. Select the GRAPH tab. Choose Temperature for the x -axis. A line with a positive slope shows that two variables are directly proportional, while a curve with a negative slope reveals that two variables are inversely proportional. Based on the graph, temperature and volume are directly proportional. This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:00^ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

indirectly proportional? directly B. Therefore, if the amount of gas is tripled, the volume will triple

  1. Summarize: Avogadro’s law states the relationship between volume and the amount of gas. State Avogadro’s law in your own words. Avogadro’s Law states that all gases have the same number of particles when there is equal volume and at the same pressure and temperature. Activity B: Pressure relationships Get the Gizmo ready: ● Select Pressure as the dependent variable. ● Set Volume ( V ) to 42.0 L, Moles ( n ) to 1.0, and Temperature ( T ) to 100 K. Introduction: Pressure refers to the force that the gas molecules exert on the walls of their container. Pressure always refers to force acting over a specific area: Pressure = Force/Area. Question: What determines how much pressure a gas will exert?
  2. Explore: Set the gas to Hydrogen. Observe how often the gas molecules collide with the bottom of the chamber. Now increase the temperature and observe the number of collisions. A. What happens to the speed of molecules as temperature increases? The speed increases B. What happens to the number of collisions as temperature increases? The number of collisions increases C. What happens to the pressure as temperature increases? The pressure increases D. Based on your observations, why do you think the pressure increases? I think the pressure increases because when the temperature goes up the number of collisions hitting the container leads to a build up of pressure. Meaning that pressure and temperature are proportional in some way.
  3. Graph: Create a graph that shows the relationship between temperature and pressure. A. Is the relationship between the temperature and pressure directly or indirectly proportional? directly proportional B. Therefore, if the temperature is quadrupled, the pressure will be quadrupled
  4. Summarize: The relationship between pressure and temperature (at constant volume) is given by Gay-Lussac’s law. State Gay-Lussac’s law in your own words. This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:00^ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Gay-Lussac’s law states that pressure is directly proportional to the temperature when there is a constant volume.

  1. Investigate: Select the BAR CHART tab. Make the chamber as large as possible. A. Gradually decrease the volume. What happens to the pressure of the gas? The pressure increases B. What happens to the pressure when the volume is cut in half? The pressure is doubled C. What happens to the pressure when the volume is quadrupled? When pressure is halved by 3 D. How does volume affect pressure? As the volume goes up it causes the pressure to decrease and when the volume goes down the pressure goes up meaning they are inversely proportional
  2. Graph: Create a graph showing the relationship between volume and pressure. A. Is the slope of the line positive or negative? negative B. Based on the direction of the slope, is the relationship between pressure and volume directly or inversely proportional? inversely proportional C. Which gas law summarizes this relationship? Boyle’s Law D. Why do you think making the chamber smaller leads to an increase in gas pressure? When the chamber is smaller the pressure increases causes the particles of gas to hit the lid and walls more often. More collisions means more pressure.
  3. Observe: Select the BAR CHART tab. Change the number of moles and observe. A. What happens to the pressure as the amount of gas increases? The pressure also increases B. What is the relationship between the number of moles and pressure? When there is a constant temperature and pressure the number of moles and pressure are directly proportional meaning that if one goes down so will the other and if one goes up so will the other.
  4. Infer: One mole of any substance contains Avogadro’s number (6.022 × 1023 ) of particles. A. Will doubling the number of moles double the number of particles? Yes it does B. Why does doubling the number of moles double the pressure? This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:00^ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
  1. Synthesize: If you know that ab and ac , then you can also say that abc , or the product of b and c. Take the above three proportionalities (including Vn ) and combine them into a single proportionality in the form: V ∝? Show your work below. V ∝ T V ∝ n V ∝ 1/P V ∝ T1/Pn
  2. Calculate: A proportionality is not the same thing as an equation, however. To convert a proportionality into an equation it is necessary to multiply by a mathematical constant. For example, ab means that a = kb , where k is a constant. When referring to gases, this constant is referred to as R, the ideal gas constant. A. In the space below, rewrite the proportionality you created in question 2 so that the proportionality symbol (∝) is changed to “=” and the right side is multiplied by R. V=nRT/P B. Rearrange your equation to solve for the ideal gas constant: R = PV/nT C. You should have gotten an equation equivalent to ( R = PV / nT ). Pick any set of conditions in the Gizmo you would like, and then calculate R. Show your work below. P = 1.6/2.0 V = 17.2/4. n = 0.8/0.2 T = 420/500 R = 0. D. Recalculate R using a completely different set of Gizmo conditions R = 0.
  3. Compare: The accepted value for R is 0.08206 L·atm/K·mol or 8.314 L·kPa/K·mol, depending on the unit of pressure used. (Your answer may differ slightly due to rounding.) How close was your calculation? It was decently close they were both in the 0.08 range
  4. Synthesize: The ideal gas law is an equation relating P , V , R , n , and T. Rewrite the formula you found in question 3A so that P and V are on one side and R , n , and T are on the other. Show your work. PV = nRT
  5. Discover: It is important to have a baseline set of conditions to serve as a reference point. Standard temperature and pressure ( STP ) is defined as 1 atmosphere (atm) or 101.325 kilopascals (kPa) of pressure at 273 K (0 ºC). STP reflects normal atmospheric conditions at sea level. A. Use the Gizmo to find the volume of 1 mole of gas at STP. (You will need to manually enter the temperature.) What value did you find? 22.4 L This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:00^ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

B. Choose a different gas. Does the volume change? No

  1. Calculate: Use the ideal gas law ( PV = nRT ) to solve the following. Show work for each problem. Then use the Gizmo to check your answer. A. What is the volume of 0.5 moles of gas at STP? P = 1 V= ?? n=0. R= 0. T= 273 K (0.5)(0.08206)(273)/(1) = 11. Rounded = 11. V = 11.2 L B. How much pressure would 0.8 moles of a gas at 370 K exert if it occupied 17.3 L of space? P = ?? V= 17. n=0. R= 0. T= 370 K (0.8)(0.08206)(370)/(17.3) = 1. Rounded = 1. P = 1.4 atm C. How much H 2 gas is necessary to exert a pressure of 1.4 atm at 430 K if occupying a volume of 15.1 L? P = 1. V= 15. n=?? R= 0. T= 430 K (1.4)(15.1)/(0.08206)(430) = 0. Rounded = 0. n = 0.6 mol This study source was downloaded by 100000821074497 from CourseHero.com on 01-18-2022 21:12:52 GMT -06:00^ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved Powered by TCPDF (www.tcpdf.org) https://www.coursehero.com/file/89728315/Copy-of-IdealGasLawSEpdf/