Pressure and Gas Relationships

Pressure and Gas Relationships

Start

Activity 3

30:00

Activity 2

We have been exploring gas behavior in order to understand the heated soda can experiment from Activity 1. In Activity 2 we were able to see that the pressure of a gas increases as the amount of gas increases, with the volume and temperature remaining constant. We also concluded that the small particles making up the gas must be colliding with the walls of the container, and that pressure is related to the number of collisions per second between the particles and the wall of the container. Because we heated the air in the soda can in Activity 1 and then cooled the can down, we will also need to investigate how temperature of a gas is related to its pressure.

purpose

In this activity we will investigate what happens to air pressure when theamount of air changes. It is important that we try to minimize the effect ofchanging the volume and temperature (we will explore their effect on thepressure later). In order to make sure that any changes in pressure we see are due to the changes in the amount of gas ONLY, we will have to make sure that the volume and the temperature remain the same. We say that we are holding volume and temperature constant.

Agenda

• PC: ACTIVITY 2

• BREAK

• PC: ACTIVITY 3

• CONCEPT MAP

• CER TICKET

ACTIVITY 2: An Introduction to Pressure

1. How are the macroscopic properties of pressure and the amount of gas related? 2. What does this relationship tells us about the makeup of a gas like air?

Exploration #1: How does the amount of air in a container affect the pressure exerted by that air?

You will need: Ø Safety goggles Ø 250 mL Conical flask Ø 1 hole stopper Ø Valve fitting Ø Pressure sensor connector ØPressure sensor and data collection device Ø 60 mL syringe Ø Balance accurate to 0.01 grams Ø Small ribbon of tissue paper

Exploration #1: How does the amount of air in a container affect the pressure exerted by that air?

You will need: Ø Safety goggles Ø 250 mL Conical flask Ø 1 hole stopper Ø Valve fitting Ø Pressure sensor connector ØPressure sensor and data collection device Ø 60 mL syringe Ø Balance accurate to 0.01 grams Ø Small ribbon of tissue paper

Exploration #2: Testing the Idea of Particles

You will use you a simulation from PhET called Gas Properties because it simulates the behavior of gases in different circumstances. STEP 1. Open the simulator and click on the box that says ‘Ideal.’ STEP 2. Put one pump of gas into the container and make some initial observations.

ACTIVITY 3: Pressure and Temperature Relationship

1. How are the macroscopic properties of temperature and pressure of gas related? 2. What does this relationship tells us about the behavior of the small particles of gases? 3. In the Air Can Experiment, why didn’t the can collapse when it was hot?

Exploration #1: Gas Pressure and Temperature Relationship

You will need: Ø Safety goggles Ø Pressure sensor Ø Temperature probe Ø Data collection device Ø 125 mL conical flask Ø Two-holed stopper to fit the flask (one of the holes has a closed valve as pictured) Ø Tubing with fitting connectors Ø 600 mL beaker

Exploration #2: Exploration of Temperature and Pressure using the Simulator.

Part 1: Pressure vs. Temperature (keeping the amount of gas and volume constant) Earlier we defined pressure as force/area. In this activity we observed that pressure increased when we heated the gas. STEP 1: Open the simulator and click on the “Energy” box. For this exploration, the volume of the container with the gas particles will not change

Exploration #3: Modeling the energy flow and making inferences about the particles.

Pressure ~ # of collisions/sec/area x ”Oomph” /collision This relationship is referred to as the Small Particle Theory (SPT) Mechanism for Pressure

Pressure and Gas Relationships

concept map

How are the macroscopic properties of temperature and pressure of gas related?

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