Pierra Flack - Gizmo Equilibrium and Pressure.docx - Name...

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2019 Name: ______________________________________ Date: ________________________ Student Exploration: Equilibrium and Pressure [Note to teachers and students: This Gizmo was designed as a follow-up to the Equilibrium and Concentration Gizmo. We recommend doing that activity before trying this one.] Vocabulary: Dalton’s law, Le Châtelier’s principle, partial pressure, pressure Prior Knowledge Questions (Do these BEFORE using the Gizmo.) A typical scuba tank has a volume of 11 liters and can support a diver for one hour. An adult breathes about 3 liters of air with each breath. 1. How can an 11-liter tank give a diver enough oxygen for one hour? The deeper you go the more pressure the diver’s lung are under. The added pressure means less air is required for respiration. 2. Why are diving cylinders made of thick, reinforced aluminum or steel? To withstand the pressure exerted by the water the deeper they go down. Gizmo Warm-up Gases consist of billions of tiny particles in constant motion, colliding with each other and the walls of the container. The sum of all these collisions creates pressure on the walls of the container. In theory, any amount of gas can be squeezed into a container if the container is strong enough to withstand the gas pressure. The Equilibrium and Pressure Gizmo shows a mixture of gases in a chamber. The lid of the chamber can move up or down. 1. Check that Reaction 1 is selected. Use the Moles NO 2 slider to increase the number of NO 2 molecules in the chamber. How does this affect the volume of the chamber? As NO2 increases, the volume of fluid in the container increases so the volume of the chamber increases also and vice versa. 2. Notice the weights on the lower right side of the Gizmo. Drag several of these weights to the lid. How does this affect the volume of the chamber? Added pressure decreases the volume of the chamber.
2019 Activity A: Dalton’s law Get the Gizmo ready : Remove all weights from the lid. Set Moles NO 2 and Moles N 2 O 4 to 0. Introduction: In a mixture of gases, each gas contributes a partial pressure to the total pressure in the chamber. Because the chamber has a moveable piston, the pressure inside is equal to the pressure on the lid. In this Gizmo, the units of pressure are megapascals (MPa). Question: How do individual gases contribute to the total pressure in a chamber? 1. Observe : Set Moles NO 2 to 2 to add 2 moles of NO 2 gas to the chamber. A. The total pressure ( P ) on the chamber is shown next to the weights, at bottom right. What is the total pressure in the chamber? 54 MPa B. Select the BAR CHART tab and select Pressure . Turn on Show data values . What is the pressure of NO 2 ? P NO2 = 54.00 MPa 2. Observe : Set Moles N 2 O 4 to 2 to add 2 moles of N 2 O 4 gas to the chamber.