Prior Knowledge Questions Do these BEFORE using the Gizmo.

2019 Name: Date:

Student Exploration: Ideal Gas Law

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.) Why is it often necessary to add air to your car tires during the winter?The colder temperatures effect the air in the tire, they go flat faster so it’s on the safer side to make sure to get air put in them regularly.

1.Why do you think it might be a bad idea to throw an aerosol can into a fire?The minute they hit too high temperatures such as fire the liquid turns to gas.This means they become full of gas, gas and fire don’t mix well together and this thus could create an explosion of sorts.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?The pressure, and the volume becomes more condensed.What stays the same?The number of molecules and the moles hydrogen 2.Using the purple slider on the tank of gas, adjust the number of moles, or amount of gas.What changes?Volume This study source was downloaded by 100000807533334 from CourseHero.com on 06-18-2021 18:44:19 GMT -05:00

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2019 What stays the same?

Pressure and temperature 3.Now make Pressure the dependent variable. Use the red slider to change the temperature.What changes?The volume skyrockets What remains the same?Temperature and moles hydrogen

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?They’ll immediately start bouncing around much faster.

B.What do you think will happen to the space between molecules, and thus the volume of a gas, as it is heated?They’re going to start dispersing so they have more room to maneuver.

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 slowly start moving around faster.B.If the temperature of a gas is doubled, its volume will increase by 2x C.If the temperature of a gas is halved, its volume will decrease by 2x.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 This study source was downloaded by 100000807533334 from CourseHero.com on 06-18-2021 18:44:19 GMT -05:00

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2019 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.

2.Summarize : Charles’s law states the relationship between the temperature and volume of a gas. Based on your observations so far, state Charles’s law in your own words.If temperature is affected then we will be able to tell by checking the volume of the molecules, they are directly related.(Activity A continued on next page) Activity A (continued from previous page) 3.Explore : Select the TABLE tab. Note the container’s lid, which exerts pressure on the gas.A.What do you think will happen to the volume of the gas as pressure is increased?They’ll start moving around faster.B.Gradually increase the pressure. Record data each time. How does volume change when pressure increases?The Volume is double by two.C.What happens to the volume when the pressure doubles?The volume is subsequently halved.D.Is this relationship directly or inversely proportional?Inversely 4.Summarize : The relationship between pressure and volume is summarized by Boyle’s law.Based on your observations, state Boyle’s law in your own words.If the pressure is changed the volume will reflect this change. They are inversely proportional .

5.Predict : Check that Volume is still the dependent variable. Set Moles to 0.2 mol.

A.Predict: If more gas is added to the chamber, the volume will increase.

B.Gradually introduce more gas into the chamber. Was your prediction correct? No. This study source was downloaded by 100000807533334 from CourseHero.com on 06-18-2021 18:44:19 GMT -05:00

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2019 6.Investigate : On the DESCRIPTION tab, change the gas to helium and then to nitrogen.Experiment with the Gizmo, noting if the volume changes as the type of gas is changed.A.Does the identity of the gas affect the volume of the gas?No it doesn’t.B.Why do you think this is so? Because you’re just changing the gas, if the pressure and temperature are still the same, the volume isn’t going to do anything.

7.Graph : Create a graph that shows the relationship between volume and number of moles.A.Is the relationship between the amount of gas (indicated by moles) and the volume directly or indirectly proportional?Directly B.Therefore, if the amount of gas is tripled, the volume will triple as well.

8.Summarize : Avogadro’s law states the relationship between volume and the amount of gas. State Avogadro’s law in your own words.

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?

1.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?It gets faster.

B.What happens to the number of collisions as temperature increases?They lessen.C.What happens to the pressure as temperature increases?There’ s not as much pressure which gives the molecules that room to move around.D.Based on your observations, why do you think the pressure increases? This study source was downloaded by 100000807533334 from CourseHero.com on 06-18-2021 18:44:19 GMT -05:00

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