**SAMPLE CALCULATION **

**OBSERVATION TABLE - IN AIR AT 328K**

Now we plot a graph between (x-x_{0}) and time/(x-x_{0})

**(x-x0) vs time/(x-x0) plot **

Then for the data above we have the least square equation as :

y = 26.17x + 1159

From the graph slope S is = 2.617*10^7 sec/m^2

Operating temperature T = 328K

Vapor pressure or carbon tetrachloride can be obtained from the equation :

Where T is in K and vapor pressure is in Pascal.

For carbon tetrachloride : C_{1}=78.441 , C_{2}=-6128.1 , C_{3}=-8.5766 , C_{4}=6.8465*10^{(-6)} , C5=2

With these values of constants we have the vapor pressure to be 49512.55 pascal =49.512 kN/m^{2}

Total pressure P = 101.32 kN/m^{2}

Kilogram molecular volume of a gas = 22.4 m^{3} at 273.15 K

Molecular weight of carbon tetrachloride = 154 kg/mol

Density of carbon tetrachloride at 321K = 1540 kg/ m^{3}

Total concentration

=.03716kmol/m^3

Concentration of carbon tetrachloride

=.01816 kmol/m^{3}

= .0372kmol/m^{3}

=.01902 kmol/m^{3}

=.0271 kmol/m3

Diffusion co-efficient

=7.67*10^{(-6)} m^{2}/sec

Similarly repeating the experiments at different temperature we get different values for diffusion co-efficient.Thus it is seen that the diffusion coefficient is a function of time and it increases with increase in temperature.

Plot a T vs D*P on a log - log plot.

Finally from the plot we have

where b is a parameter that denotes temperature dependence and theoritically it should lie between 1.5 to 1.8