Chapter 05 - Gas Laws I - Chapter 5 Gases and the Kinetic-Molecular Theory 5-1 The Three States of Matter Gas Molecules are far apart Move freely Fill

Chapter 05 - Gas Laws I - Chapter 5 Gases and the...

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5-1 Chapter 5 Chapter 5 Gases and the Kinetic-Molecular Theory Gases and the Kinetic-Molecular Theory
5-2 The Three States of Matter The Three States of Matter Gas • Molecules are far apart • Move freely • Fill available space: shape and volume of flask Liquid • Molecules are close together • Move around each other • Take shape but not volume of flask Solid • Molecules are very close together in a regular array Do not move around each other • Do not take shape or volume of flask
5-3 States of Matter States of Matter Gases, Liquids, and Solids Differences based on relationships among particles Average distance between particles Average distances in gas phase larger than in liquid phase Tight packing in solid phase Types of interactions between particles Higher degree of interactions in solids than in gases Electrostatic interactions in solids Type and degree of organization of particles Solids highly organized Liquid less organized Gases disordered
5-4 Differences Between Gases, Liquids and Solids Differences Between Gases, Liquids and Solids Gas Gas Liquid Solid Solid Volume and Shape Expands to fill container Takes shape of container Fixed volume at given mass and temperature Takes shape of container, not volume of container Fixed volume Definite shape Density Low High High Compressibility High Very low Virtually incompressible Particle Motion Virtually free Atoms and molecules “slide” past each other Vibration around fixed position Intermolecular distance Very large Atoms or molecules close to each other Molecules, ions or atoms very close to each other
5-5 Experimental Gas Laws Experimental Gas Laws Physical behavior of gases dependent on pressure, P volume, V temperature, T amount in moles, n Variables are interdependent: Any variable can be determined by measuring the other three Relationships expressed by Boyle’s Law: dependence of volume on pressure Charles’ Law: dependence of volume on temperature Avogadro’s Law: dependence of volume on amount Ideal Gas Law: expresses all gas laws in one equation PV = nRT Study
5-6 Barometer - measures atmospheric pressure Invented by Evangelista Torricelli A commonly used unit of pressure is the atmosphere (atm). 1 atm is equal to: 760 mmHg 760 torr 76 cmHg The Gaseous State and the Experimental Gas Laws The Gaseous State and the Experimental Gas Laws
5-7 Pressure - force per unit area Gas pressure is a result of force exerted by the collision of gas molecules with the walls of the container The Gaseous State and Pressure The Gaseous State and Pressure Unit Unit Scientific Field Scientific Field 1 atm = 760 mmHg = 29.91 in 1 atm = 760 mmHg = 29.91 in Chemistry, Medicine, Chemistry, Medicine, Biology Biology 1 atm = 1.01325 x 10 5 Pa (= N/m 2 , SI system) Physics, Chemistry 1 atm = 1.01325 bar Meteorology 1 atm = 14.7 psi Engineering 1 mm Hg = 1 torr Chemistry
5-8 Boyle’s Gas Law Boyle’s Gas Law P x V = c P x V = c

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