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Chapter 3 – States of Matter. Kinetic Theory. Kinetic energy = energy an object has due to its motion The faster an object is moving; the greater its kinetic energy. Kinetic theory states that all particles of matter are in constant motion. 3.1 Solids, Liquids, and Gases. Solids
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Kinetic Theory • Kinetic energy = energy an object has due to its motion • The faster an object is moving; the greater its kinetic energy. • Kinetic theory states that all particles of matter are in constant motion.
3.1 Solids, Liquids, and Gases • Solids • Definite Shape • Definite Volume • Particles vibrate in fixed positions • Particles have low kinetic energy
Liquids • Variable shape (takes the shape of the container) • Definite Volume • Particles can move around each other • Particles have medium Kinetic Energy
Gases • Variable shape • Variable volume (fills all space in a container) • Particles move about freely • Particles have high Kinetic Energy
Other states of matter • Plasma • Exists only at extremely high temperatures • 99% of the matter in the UNIVERSE is plasma • Stars are plasma • Bose-Einstein Condensate • Exists only at extremely low temperatures • Groups of atoms behave as a single particle
3.2 The Gas Laws • Pressure = the result of force distributed over an area • In a closed container, gases exert pressure when the particles of the gas collide with the walls of the container. • More Collisions=More Pressure • Forces of attraction among gas particles so weak they can be ignored under ordinary conditions
Factors That Affect Gas Pressure • Temperature – raising temp. will increase pressure if volume of gas and # of particles are kept constant • Increase in temp. particles move faster particles collide with walls more frequently increased pressure
Factors That Affect Gas Pressure Cont….. • Volume – Decreasing volume of a gas causes an increase in pressure if the temp. and # of particles are constant • Decrease in vol. less space particles collide with walls more often increase pressure
Factors That Affect Gas Pressure Cont….. • Number of particles – increasing the number of particles of a gas will increase pressure if temp. and volume are constant • Increase # of particles particles collide with container more often increase pressure
V T Charles’ Law • The volume and absolute temperature (K) of a gas are directly related • at constant mass & pressure • V1 = V2 • T1 T2
Boyle’s Law • P1V1 = P2V2 • The pressure and volume of a gas are inversely related • at constant mass & temp
P1V1 T1 P2V2 T2 = Combined Gas Law P T V T PV T PV = k P1V1T2 =P2V2T1
https://www.youtube.com/watch?v=Osq71Y82uac • https://www.youtube.com/watch?v=kr1V0KtZPGw
3.3 Phase Changes • Phase change – reversible physical change that occurs when a substance changes from one state of matter to another • Temperature of a substance DOES NOT CHANGE during a phase change. • Energy is either absorbed or released during a phase change. • Endothermic – energy is absorbed • Exothermic – energy is released
Melting and Freezing • Melting • Solid changes to liquid • Particles absorb energy (endothermic) • Particles become less orderly • Heat of fusion- energy a substance must absorb in order to change from solid to liquid • Freezing • Liquid changes to solid • Particles release energy (exothermic) • Particles become more orderly
Vaporization and Condensation • Vaporization • Liquid changes into a gas • Particles absorb energy (endothermic) • Particles become LESS orderly and more free to move • 2 types of vaporization • Evaporation – takes place at the surface of a liquid • Boiling – occurs when a liquid is heated to its boiling point
Condensation • Gas changes to a liquid • Particles release or lose energy (exothermic) • Particles become MORE orderly
Sublimation and Deposition • Sublimation • Changing from a solid directly to a gas • Energy is absorbed (endothermic) • Deposition • Changing from a gas directly to a solid • Energy is released (exothermic)