Presentation on theme: "The Kinetic Theory of Matter"— Presentation transcript:
1The Kinetic Theory of Matter Chapter 10The Kinetic Theory of Matter
210.1 Physical Behavior of Matter States of Mattersolidliquidgas
3Intermolecular Forces (IMF) Attractive forces between molecules.Much weaker than chemical bonds within molecules.
4The Kinetic Theory of Matter 1. Matter is composed of PARTICLES.2. Particle movement is rapid, constant, and random (Brownian motion)
5The Kinetic Theory of Matter 3.All collisions are perfectly ELASTIC (NO energy lost).
6Kinetic theory of matter Kinetic energy (K.E.) = energy of motiongases have the least restriction on motionhave the most K.E.solids have the most restriction on motionhave the least K.E.
7Kinetic model of gasesGases: matter with variable shape and variable volumeGas particles move ina straight line until theycollide with container oreach other
8Kinetic model of gasesDiffusion- random motion of gas particles that spread out and fill a space
9Kinetic model of gasesideal gas—gases with perfectly elastic collisions and no intermolecular forcesMost real gases behave as ideal gases except at very low temps and very high pressures
10Kinetic model of gasespressure – force acting on a unit area of surfacegas pressure— collisions of gas particles on objects
11Kinetic model of gasesatmospheric pressure— collisions of “air” particles on objects
12STANDARD ATMOSPHERIC PRESSURE: Kinetic model of gasesSI unit of pressure = Pa (Pascal)standard pressure: (this is the “P” from STP)STANDARD ATMOSPHERIC PRESSURE:1 atm = 760. mm Hg = 760. torr = kPa = 14.7 psiPsi = pounds per square inchmmHg = millimeter of mercuryAtm – atmospherekPa – kilopascalsTorr - torr
13examples of pressure conversions 1) Convert a pressure of 847 mm Hg to kPa.847 mm Hg x kPamm Hg2) What is 8.9 psi expressed in atm?8.9 psi x atmpsi= 113 kPa= 0.61 atm
143) 344 mm Hg = _____ psi = 6.65 psi 344 mm Hg x 14.7 psi___
15Kinetic model of liquids Liquids: matter with variable shape and definite volumeParticles slide past eachother but are so closetogether they do not movein a straight line
16Kinetic model of solids solids: matter with definite shape and definite volumeParticles cannot move past each other, they are in constant motion bouncing off neighbors
17Crystalline solids Types of solids a) crystal lattice—organized repeating pattern in 3-Db) unit cell—smallestrepeating unit in a crystal
18Crystalline solids continued c) allotropes— two or more different arrangements for the same element in the same state (C: graphite, diamond)
19Types of solids 2.amorphous— solids without a set structure incomplete crystal lattice formedb) rubber, plastics, glass Candles, peanut butter, cotton candy
20Other forms of matter1. amorphous solids 2. liquid crystals—an intermediate phase formed when solids partially melt in only one or two dimensions and can flow like a liquid (LCD = liquid crystal display)
21Other forms of matter 3. Plasmas gaseous mixture of ions -exists at high temperaturesmost common form of matter in the universe but least common on Earth itself
22Plasmas continuedan ionized gas that conducts electricity -forms at very high temps when matter absorbs energy and breaks apartThe sun is made of plasma- also found in fluorescentlights
2310.2 – Kinetic energy and changes of state Temperature and kinetic energytemperature—the measure of the average K.E. of particles in a sampleKelvin (K) – SI base unit of temperature; measures average K.E.
24Temperature and kinetic energy When temp increases, particle motion increases.When temp decreases, particle motion decreases.A temp of 300 K has twice the kinetic energy as 150 K.
25Temperature and kinetic energy 0 Kelvin = absolute zero = no molecular motionNo degrees sign ( ° ) is used with Kelvin numbersThere will never be negative numbers for Kelvin temperatures!.
26Temperature Scales Fahrenheit Celsius Kelvin Anders Celsius 1701-1744 Lord Kelvin(William Thomson)
27Temperature Scales Notice that 1 kelvin = 1 degree Celsius Fahrenheit Boiling point of water32 ˚F212 ˚F180˚F100 ˚C0 ˚C100˚C373 K273 K100 KFreezing point of waterNotice that 1 kelvin = 1 degree Celsius
28ElementFreezing Point, ºCBoiling Point, ºCOxygen-219-183Chlorine-101-34Nickel14552913Phosphorus442801. Which of the elements are gases at 50ºC? At -50ºC?2. Which of the elements are liquids at 50ºC? At -50ºC?3. Which of the elements are solids at 50ºC? At -50ºC?4. Which element has the smallest temperature range as a liquid? The largest temperature range?
29Converting Temperature Kelvin-Celsius conversion equation K = C Express K in degrees Celsius. K = C = C C = 93 °C Convert a temperature of 45 °C to Kelvin. K = C K = = 318 K
30Fahrenheit / Celsius Formulas °F = 9/5 °C(°F - 32) * 5/9 = °CA person with hypothermia has a body temperature of 29.1°C. What is the body temperature in °F?°F = 9/5 (29.1°C)== 84.4°F
31Changing statesvaporization - conversion of a liquid to a gas or vapor below the boiling point (b.p.)evaporation rate – depends on surface area, temp, and humidity
32b) condensation—conversion from a gas or vapor to a liquid
33Changing statesc) sublimation—changing from a solid directly to a vapor (w/o becoming liquid first) EX: dry ice, mothballs, solid air fresheners
34d) deposition—changing from a vapor/gas directly to a solid (w/o becoming liquid first)
35What type of phase change is occuring? 1. solid carbon dioxide(dry ice)to carbon dioxide gas2. ice to liquid water3. liquid bromine to bromine vapor4. liquid water to ice5. water vapor to liquid watersublimationmeltingvaporizationfreezingcondensation
36Vapor Pressure and boiling Vapor Pressure - pressure of vapor above a liquid at equilibriumhigh vapor pressure = volatilevolatile = easily evaporatesThe greater the fraction of molecules which can escape the liquid, the greater the vapor pressure
37At some point in time the number of vapor molecules rejoining the water equals the number leaving to go into the vapor phase
38Vapor pressure and boiling point Boiling Point - temp at which v.p. of liquid equals external pressure-depends on atmosphericpressure & IMFNormal B.P. - b.p. at 1 atmWhen the vapor pressure of a liquid equals atmospheric pressure, the liquid has reached its boiling point, which is 100°C for water at sea level.At this point, molecules throughout the liquid have the energy to enter the gas or vapor phase.
39Effects of Intermolecular Forces (IMF) When IMF’s are weakvapor pressure is highvolatility is highboiling point is low
40Heat of Vaporization Joule (J) – the SI unit of energy heat of vaporization – the amount of heat necessary to boil 1 mole of a substance at its boiling point
41Heat of FusionMelting point – temp of a solid when it becomes a liquid= freezing point (temp when liquid becomes a solid)heat of fusion – energy needed for 1kg of a substance to solidify at it’s freezing point
42Freezing/Melting point B. Heating CurvesGasBoiling pointLiquidFreezing/Melting pointSolid
43Changing state IMPORTANT: temp does not change during a phase change. Increasing the temp will only make the change happen faster.
44Phase DiagramsShows the phases of a substance at different temps and pressures.
45triple point -the point on a phase diagram that represents the temperature and pressure at which three phases of a substance can coexist.All six phase changes can occur at the triple point: freezing and melting, evaporation and condensation, sublimation and deposition.
46Phase Diagramscritical point -the critical pressure and critical temperature above which a substance cannot exist as a liquid.