1. - - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - --
TRANSPORT PROPERTIES
Ch 30
Quantity
Gradiant
Laws
Temperature
Heat
HOT
- +
Electrons
Potential
Mass
Pressure
Mass Concentration
Momentum Velocity
Flux = Jz = amount transported across unit area per s

2. Flux- Gases
Transport is by discrete carriers and each carrier transports a finite amount
In 1 second 1/6th of all molecules present in the box of dimensions
will pass through the shaded area C z
# of molecules traveling along ‘Z’ = 1 6
# of molecules crossing the face in one second = N C
If each carrier transports quantity ‘q’

3. Potential Gradient in the System
HOT
COLD T 2 1 T2 T1 Z T Z

4. Thermal Conductivity of an Ideal Gas – Part 1
Since heat is a manifestation of K.E. and is transported via collisions between carriers, we shall consider gas collisions & mean free path ‘ .’ Z C B A {  Z+ Z-
From ‘A’ to‘B’ = 1 6 N C  3 2 k [ T +  Z -  ]
From ‘C’ to ‘B’ = 1 6 N C  3 2 k [ T +  Z  ] - 1 6 N C  3 2 k [   T Z ] =

5. Thermal Conductivity of an Ideal Gas – Part 2[ -
Net Flux = = 1 6 N C  3 2 k   T Z ] =   T Z
= -

6.  = 0 =2C =sqr2C Mean free path ‘ ’ Average distance traveled in 1s =
If ‘Z’, = number collisions per s,  =
Consider a cylinder of radius,  , length
In 1s, molecule will travel from one end to the other
# collisions made by one molecule per s =
But average relative velocity =
= 0
=2C
=sqr2C
Relative Velocity
Collision number =
Mean free path =

7. Diffusion: substances diffuse from a high concentration region to a low concentration region.
Nz+ Nz
Nz- Z x
Net Flow
Homework: Poizulle Formula & Viscosimeter