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States of Matter Equations of State Ideal GasDeviations Van der WaalsVirial Series Kinetic Molecular Model Corresponding States Fluids Reduced Variables Condensed Phases Berth., R-K Mixtures
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Hi Chem.412 students, Due to a last minute appointment, there is a good chance that I will not be able to make the 9:00 a.m. class on time tomorrow (Wednesday). Therefore, I am substituting the Wednesday 9 am lecture on the next topic “Nature of Matter and Mystery of the Universe” with the following You-Tube videos: (Click on the hyperlinks to see them in sequence) Wednesday afternoon and evening labs go on as scheduled. Video #1 (explanation of the Big Bang, ~5.5 minutes) S. Hawking: Big BangS. Hawking: Big Bang Video #2 (How to find particles, ~17 min) Particle HuntersParticle Hunters Video #3 (A Rap on the LHC, ~4.5 min) HadronsHadrons [Please be somewhat skeptical and don’t take any offense regarding comments after these (free) videos … these are “uncontrolled” public comments that can be at times insensitive and offensive!] Please watch them before Friday’s class since I will be skipping the beginning parts of the next powerpoint (States of Matter). Wednesday afternoon and evening labs go on as scheduled. Dr. Ng. 9/11/13 – Lec sub
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Matter Three States of Matter LiquidGas Microscopic Molecular Size Molecular Shape Velocity/Momentum Intermolecular Forces Macroscopic Temperature Pressure Viscosity Density Solid CyberChem: Big Bang S. Hawking: Big Bang
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Mystery of our Universe: A Matter of Family ? Quarks Fermions - Particles Leptons HadronsHadrons neutron proton e - - - [ ] nuclidesatoms elements mixturescompounds moleculescomplexes homogeneousheterogeneous Bosons – Force carriers Strong (gluon) Weak (+W, -W, Z) Electromag. (photon) Gravity (graviton) Three families 1)u d e - e 2) c s - 3) t b -
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Mystery of our Universe: Quarks Particle Hunters Big Bang Theory physics episodes
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We can combine these into a general gas law: The Ideal Gas Equation Boyle’s Law: Charles’s Law: Avogadro’s Law:
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R = gas constant, then The ideal gas equation is: R = 0.08206 L·atm/mol·K = 8.3145 J/mol·K J = kPa·L = kPa·dm 3 = Pa·m 3 Real Gases behave ideally at low P and high T. The Ideal Gas Equation
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Calculate the number of air molecules in 1.00 cm 3 of air at 757 torr and 21.2 o C. Mathcad
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Calculate the number of air molecules in 1.00 cm 3 of air at 757 torr and 21.2 o C. MathcadF12
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Low P Ideal
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High T Ideal
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Gas Densities and Molar Mass The density of a gas behaving ideally can be determined as follows: The density of a gas was measured at 1.50 atm and 27°C and found to be 1.95 g/L. Calculate the molecular weight of the gas? If the gas is a homonuclear diatomic, what is this gas?Calculatewhat is Plotting data of density versus pressure (at constant T) can give molar mass. Density of an Ideal-Gas Mathcad
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Density of an Ideal-Gas Derivation of :
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Plotting data of density versus pressure (at constant T) can give molar mass.
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Molar Mass of an Non-Ideal Gas Generally, density changes with P at constant T, use power series: First-order approximation: Plotting data of ρ/P vs. P (at constant T) can give molar mass. Deviation of Density from Ideal
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Plotting data of ρ/P vs. P (at constant T) can give molar mass.
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Dalton’s Law: in a gas mixture the total pressure is given by the sum of partial pressures of each component: Each gas obeys the ideal gas equation: Ideal Gas Mixtures and Partial Pressures Density?
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Partial Pressures and Mole Fractions Let n i be the number of moles of gas i exerting a partial pressure P i, then where χ i is the mole fraction. Ideal Gas Mixtures and Partial Pressures CyberChem (diving) videoCyberChem (diving) video:
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The van der Waals Equation General form of the van der Waals equation: Real Gases: Deviations from Ideal Behavior Corrects for molecular volume Corrects for molecular attraction
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Real Gases: Deviations from Ideal Behavior Berthelot Dieterici Redlick-Kwong
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The van der Waals Equation Calculate the pressure exerted by 15.0 g of H 2 in a volume of 5.00 dm 3 at 300. K. Calculate
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The van der Waals Equation Calculate the molar volume of H 2 gas at 40.0 atm and 300. K. Calculate
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The van der Waals Equation Can solve for P and T, but what about V? Let: V m = V/n { molar volume, i.e. n set to one mole} Cubic Equation in V, not solvable analytically! Use Newton’s Iteration Method: Mathcad: Text Solution Mathcad: Matrix Solution
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Picture
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Postulates: –Gases consist of a large number of molecules in constant random motion. –Volume of individual molecules negligible compared to volume of container. –Intermolecular forces (forces between gas molecules) negligible. Kinetic Energy => Root-mean-square Velocity => Kinetic Molecular Theory
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Kinetic Molecular Model – Formal Derivation Preliminary note: Pressure of gas caused by collisions of molecules with rigid wall. No intermolecular forces, resulting in elastic collisions. Consideration of Pressure: Identify F=(∆p/∆t) ≡ change in momentum wrt time.
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x z y Wall of Unit Area A Consider only x-direction: ( m=molecule ) ( w=wall ) BeforeAfter p m =mup m ’ =-mu p w =0p w ’ =?
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Assumption: On average, half of the molecules are hitting wall and other not. In unit time => half of molecules in volume (Au) hits A If there are N molecules in volume V, then number of collisions with area A in unit time is: And since each collision transfers 2mu of momentum, then Total momentum transferred per unit time = p w ’ x (# collisions)
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Mean Square Velocity: In 3-D, can assume isotropic distribution: Substituting [eqn 3] into [eqn 2b] gives:
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Mathcad
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Molecular Effusion and Diffusion The lower the molar mass, M, the higher the rms. Kinetic Molecular Theory
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Concept of Virial Series Define: Z = compressibility factor Virial Series: Expand Z upon molar concentration [ n/V ] or [ 1/V m ] B=f(T) => 2 nd Virial Coeff., two-molecule interactions C=f(T) => 3 rd Virial Coeff., three-molecule interactions Virial Series tend to diverge at high densities and/or low T.
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Concept of Virial Series – vdw example
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Phase Changes
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Critical Temperature and Pressure Gases liquefied by increasing pressure at some temperature. Critical temperature: the minimum temperature for liquefaction of a gas using pressure. Critical pressure: pressure required for liquefaction. Phase Changes
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Critical Temperature and Pressure Phase Changes
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Phase Diagrams
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The Phase Diagrams of H 2 O and CO 2 Phase Diagrams
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Reduced Variables
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PVT Variations among Condensed Phases Brief Calculus Review
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PVT Variations among Condensed Phases
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Brief Calculus Review – F13 -1 Mathcad
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Brief Calculus Review – F13 - 2
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Brief Calculus Review – F13 - 3
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Brief Calculus Review – F13 - 4
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Brief Calculus Review – F14 -1
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Brief Calculus Review – F14 -2
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Brief Calculus Review – F14 -3
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Brief Calculus Review – F14 -4
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Exact and Partial Differentials: Tutorial A right-circular cylinder has a base radius ( r ) of 2.00 cm and a height ( h ) of 5.00 cm. (a) Find the “approximate change” in the volume ( V ) of the cylinder if r is increased by 0.30 cm and h is decreased by 0.40 cm. Express the answer in terms of cm 3. This is the “differential” volume change. Then compare to the “real” volume change from algebraic calculations of initial and final volumes. (b)Repeat for r increase of 0.10 cm and h decrease of 0.10 cm. (c)Repeat for r increase of 0.001 cm and h decrease of 0.001 cm. What is your conclusion regarding the comparisons?
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A right-circular cylinder has a base radius ( r ) of 2.00 cm and a height ( h ) of 5.00 cm.
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Mathcad-file
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A right-circular cylinder has a base radius ( r ) of 2.00 cm and a height ( h ) of 5.00 cm.
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Differential Algebra r / cmh / cm r / cm h / cm V / *cm 3 V1V2V'=V2-V1DiffDiff% 2.005.000.300000-0.4000004.40000020.0000024.334004.3340006.6000E-021.52E+00 2.005.000.100000-0.1000001.60000020.0000021.609001.6090009.0000E-035.59E-01 2.005.000.030000-0.0400000.44000020.0000020.439660.4396643.3600E-047.64E-02 2.005.000.010000-0.0100000.16000020.0000020.160100.1600999.9000E-056.18E-02 2.005.000.003000-0.0040000.04400020.0000020.044000.0439973.0360E-066.90E-03 2.005.000.000300-0.0004004.40000E-0320.0000020.004404.39997E-033.0036E-086.83E-04 2.005.000.000030-0.0000404.40000E-0420.0000020.000444.40000E-043.0003E-106.82E-05 2.005.003.00E-06-4.00E-064.40000E-0520.0000020.000044.40000E-052.9994E-126.82E-06 2.005.003.00E-07-4.00E-074.40000E-0620.00000 4.40000E-063.3846E-147.69E-07 2.005.003.00E-08-4.00E-084.40000E-0720.00000 4.40000E-072.6741E-156.08E-07
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States of Matter Equations of State Ideal GasDeviations Van der WaalsVirial Series Kinetic Molecular Model Corresponding States Fluids Reduced Variables Condensed Phases Berth., R-K Mixtures
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