Characteristics of Gaseous StateCharacteristics of Liquid StateCharacteristics of Solid StateComposition of MatterInterplay between I.P. forces & kinetic energy of particles causes: 1. Properties of each state or phase 2. Phase changesKinetic-molecular view of statesConditions for LiquefactionGeneral types of electrostatic forcesPowerPoint PresentationThe Critical PointConsequences of Critical PointSome Tcrit and Pcrit ValuesCharacteristics of Gaseous StateParticles are very far apartParticles are very far apartVery weak interparticle forcesVery weak interparticle forcesGases assume volume & shape of containerGases assume volume & shape of containerVery compressibleVery compressibleFlow readilyFlow readilyDiffusion occurs rapidlyDiffusion occurs rapidlyLarge free volume (99%, even at P=10 atm)Large free volume (99%, even at P=10 atm)Exhibit vibrational, rotational, translational Exhibit vibrational, rotational, translational motionmotionMost energetic state of matter Most energetic state of matterCharacteristics of Liquid StateParticles are close together but not as close as in a Particles are close together but not as close as in a solidsolidParticles exhibit vib. & rotational motionParticles exhibit vib. & rotational motionLiquids are more energetic than solids but less Liquids are more energetic than solids but less energetic than gasesenergetic than gasesLiquids are negligibly compressibleLiquids are negligibly compressibleLiquids assume shape of portion of container Liquids assume shape of portion of container occupiedoccupiedFlow readily & particles diffuse slowlyFlow readily & particles diffuse slowlyLiquids have 3% free volumeLiquids have 3% free volumeModerately strong interparticle forcesModerately strong interparticle forcesCharacteristics of Solid StateParticles are very close together (most solids are Particles are very close together (most solids are close-packed)close-packed)Very strong interparticle forcesVery strong interparticle forcesMost are Most are crystallinecrystallineSome are Some are amorphousamorphous (e.g., gels, plastics, glasses) (e.g., gels, plastics, glasses)Least energetic state of matterLeast energetic state of matterParticles exhibit only Particles exhibit only vibrationalvibrational motion motionAre incompressibleAre incompressibleRetain own shape and volume Retain own shape and volume Extremely small free volume (<0.1%??)Extremely small free volume (<0.1%??)RigidRigidDiffusion occurs extremely slowlyDiffusion occurs extremely slowlyComposition of MatterMatter is composed of:Matter is composed of: 1. Atoms 1. Atoms 2. Ions 2. Ions 3. Molecules3. MoleculesPotential energy develops between particlesPotential energy develops between particles 1. Results from attractive & repulsive 1. Results from attractive & repulsive forces called interparticle (I.P.) forcesforces called interparticle (I.P.) forcesInterplay between I.P. forces & kinetic energy of particles causes:1. Properties of each state or phase2. Phase changesKinetic-molecular view of statesWhether a substance is a gas, liquid, or Whether a substance is a gas, liquid, or solid is determined by interplay between:solid is determined by interplay between: 1. P.E. of interparticle interactions1. P.E. of interparticle interactions P.E. = zP.E. = z11zz22ee22/r/r22 (Coulomb’s Law) (Coulomb’s Law) 2. Kinetic energy of particles2. Kinetic energy of particles K.E. = EK.E. = EKK=1/2 m=1/2 m22 where where ==3RT/MM 3RT/MMConditions for Liquefaction•T < TT < Tcriticalcritical•P sufficient to bring molecules close enough P sufficient to bring molecules close enough for P.E.for P.E.interparticle attractionsinterparticle attractions > E > EkinetickineticGeneral types of electrostatic forces•IntramolecularIntramolecular a. Exist within each molecule or polyatomic iona. Exist within each molecule or polyatomic ion b. Influence the b. Influence the chemicalchemical properties of the properties of the substancesubstance•Intermolecular (interparticle)Intermolecular (interparticle) a. Exist between atoms, molecules, or ionsa. Exist between atoms, molecules, or ions b. Influence the b. Influence the physicalphysical properties of the substance properties of the substanceFor example, the chemical behavior of water is identical in each of its three states because, in each state, its geometry is bent, it is polar, and the atoms in each water molecule are held together by the same intramolecular forces (polar covalent bonds)The physical behavior of water varies greatly because of the extent of interparticle forces (hydrogen bonds) in each state.The Critical PointWhen a liquid is heated in a When a liquid is heated in a closedclosed container, container,boiling does not occur; instead temp. and vaporboiling does not occur; instead temp. and vaporpressure rise continuously. Eventually pressure rise continuously. Eventually criticalcriticalpoint point is reached.is reached. 1. d1. dliqliq decreases & d decreases & dvaporvapor increases so that increases so that ddliqliq = d = dvaporvapor 2. Surface tension of liquid approaches 02. Surface tension of liquid approaches 0 3. Meniscus disappears3. Meniscus disappears 4. Liquid and vapor become indistinguishable4. Liquid and vapor become indistinguishable 5. Is highest temperature-pressure point on v. p. curve5. Is highest temperature-pressure point on v. p. curve 6. Represents highest temp. at which the liq. can exist 6. Represents highest temp. at which the liq. can exist 7. T7. Tcritcrit is temp. at critical point; P is temp. at critical point; Pcritcrit is pressure at is pressure at critical pointcritical pointConsequences of Critical PointGases having TGases having Tcritcrit > room temp. can be > room temp. can be liquefied by applying sufficient pressure.liquefied by applying sufficient pressure.Gases having TGases having Tcritcrit < room temp. can be < room temp. can be liquefied by increasing pressure liquefied by increasing pressure andand lowering the temp. below Tlowering the temp. below TcritcritSome Tcrit and Pcrit ValuesSubstanceSubstanceTTcritcrit, K, KPPcritcrit, atm, atm HH22 33.333.3 12.8 12.8 NN22 126.2 126.2 33.5 33.5 OO22 154.8 154.8 50.1 50.1 CHCH44 191.1 191.1 45.8 45.8 COCO22 304.2 304.2 72.9 72.9 HH22OO 647.3