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2019Name: ______________________________________Date: ________________________Student Exploration: Equilibrium and Pressure[Note to teachers and students: This Gizmo was designed as a follow-up to the Equilibrium and ConcentrationGizmo. We recommend doing that activity before trying this one.]Vocabulary:Dalton’s law, Le Châtelier’s principle, partial pressure, pressurePrior 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 areunder. The added pressure means less air is requiredfor 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-upGases consist of billions of tiny particles in constant motion,colliding with each other and the walls of the container. The sum ofall these collisions creates pressureon the walls of the container.In theory, any amount of gas can be squeezed into a container if thecontainer is strong enough to withstand the gas pressure. The Equilibrium and Pressure Gizmo shows a mixture of gases in achamber. The lid of the chamber can move up or down.1.Check that Reaction 1is selected. Use the Moles NO2slider to increase the number of NO2molecules 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.
2019Activity A: Dalton’s lawGet the Gizmo ready: Remove all weights from the lid.Set Moles NO2and Moles N2O4to 0.Introduction: In a mixture of gases, each gas contributes a partial pressureto 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 NO2to 2 to add 2 moles of NO2gas 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 MPaB.Select the BAR CHART tab and select Pressure. Turn on Show data values.What is the pressure of NO2?PNO2= 54.00 MPa2.Observe: Set Moles N2O4to 2 to add 2 moles of N2O4gas to the chamber.