Download presentation

Presentation is loading. Please wait.

Published byAldo Jent Modified over 3 years ago

1
32W MW (kg/mol) T (K)P (torr)P (Pa)A (m 2 ) /4N/VdN/dt (s -1 ) dN/dt (g/hr) 0.1838545004.986640.0000011801.07E+221.923E+182.113 dN/dt = A /4 N/V Density - # molecules are available for collision (m -3 ):N/V = PN A /(RT) = {8RT/( M)} 1/2 19.32Tungsten effusion – MW = 0.18385 kg/mol Given: T = 4500 K - dN/dt = 2.113 g/hour - A = 1.00 mm 2. find P W at 4500K? Convert all units to SI and find /4 Find N/V from effusion equation Solve for P – which will represent Tungsten vapor pressure For Friday do 19.28 and 19.31

2
Chemical Systems The state of a system is defined by indicating the values of the measurable properties of the system. System vs. surroundings Properties of a system …. intensiveextensive independent of amountdependent on amount P and TV, n, & all forms of energy E, U, H, S, G …. etc. extensive per mole molar volume (V, V/n or V m ) molar enthalpy or H m

3
T is a measure of how much kinetic energy the particles of a system have. translational energy, tr = 3kT/2 or E tr = 3nRT/2 Heat, q, is the transfer of energy from one system to another due to a difference in temperature. A B C T A > T B = T C A B C T A = T B = T C

4
Equations of state ….. PV = nRT or PV m = RT Partial derivatives: (dP/dT) n,V = nR/V (dV/dT) n,P = ? (dP/dV) n,T = ? nR/P PV = nRT P = nRT/V = nRTV -1 -nRTV -2 or -nRT/V 2

5
Kinetic Molecular Theory (KMT) Assume: 1. gas particles have mass but no volume 2. particles in constant, random motion 3. no attractive/repulsive forces 4. conservation of energy at every collision Real Gases: Z = PV m /RT 1 Z is a measure of nonideality of gas If … PV m = RT then … Z = PV m /RT = 1 Z is called the compressibility factor Real Gases: Z = 1 + B/V m + C/V m 2 + D/V m 3 + … Virial Equation: power series with respect to V B, C, etc. are dependent on T as well as gas.

6
Van der Waals Equation P meas = P real < P id V real < V id = V meas Ideal V = volume of container will V real be less or more than that? Ideal P = assumes no molecular interactions Do gas molecules attract or repel? How will this effect P meas ?

7
Van der Waals Equation (P + a/V m 2 )(V m - b) = RT P meas = P real < P id V real < V id = V meas a = f(intermolecular forces) units = atm cm 6 mol -2 b = molecular volume units = cm 3 mol -1 P vdw = RT/(V m – b) – a/V m 2 (P + n 2 a/V 2 )(V - nb) = nRT

8
Z P (atm) ideal real VdW RK CH 4 gas at 300K

9
Z P atm He Ne Ar Kr Xe Rel Value Gas MW (kg/mol)ab He 0.004 3.41E+0423.65 Ne 0.020 2.09E+0516.97 Ar 0.040 1.34E+0632.21 Kr 0.084 2.29E+0639.58 Xe 0.131 4.11E+0651.24

10
Van der Waals Equation (P + a/V m 2 )(V m - b) = RT a = f(intermolecular forces) units = atm cm 6 mol -2 b = molecular volume units = cm 3 mol -1 P vdw = RT/(V m – b) – a/V m 2 (P + n 2 a/V 2 )(V - nb) = nRT Critical Values – Experimentally determined from phase diagrams (Chapter 6) P c, T c, and V c are constant and unique to each gas. b = RT c /(8P c ) a = 27R 2 T c 2 /(64P c 2 )

11
Partial derivatives dP/dT = nR/V (P + a/V m 2 )(V m - b) = RT PV = nRT & P = nRT/V P vdw = RT/(V m – b) – a/V m 2 dP/dT = R/(V m -b) = nR/(V-nb)

12
Partial derivatives dP/dT = nR/V P, T, V The cyclic rule for partial derivatives (chain rule) (dP/dT) V (dT/dV) P (dV/dP) T = -1 = 1/V (dV/dT) P (expansion coefficient) = -1/V (dV/dP) T (isothermal compressibility) (dP/dT) V = - (dV/dT) P /(dV/dP) T = (dx/dy) z (dy/dz) x (dz/dx) y = -1

Similar presentations

Presentation is loading. Please wait....

OK

The Gaseous State Chapter 12 Dr. Victor Vilchiz.

The Gaseous State Chapter 12 Dr. Victor Vilchiz.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on water transport in india Ppt on english grammar in hindi Ppt on earth hour 2015 Ppt on types of poetry Ppt on mahatma gandhi biography Ppt on number system for class 5 Ppt on effect of global warming on weathering Ppt on applied operational research course Ppt on condition monitoring definition Ppt on networking related topics about information