I am going to explain the behavior predicted

by Raoult’s Law which essentially occurs when we have an ideal gas in the vapor phase mixture

in equilibrium with a liquid mixture that is an ideal liquid. Essentially it says that

the partial pressure of component 1 is proportional to the mole fraction in the liquid phase times

the saturation pressure. So “x” is the mole fraction in the liquid phase and “y” is the

mole fraction in the gas phase or the vapor phase. If we look at a plot of pressure vs.

mole fraction we can see that pressure vs. “x1” is a straight line. This is the green

line. Similarly pressure vs. “x2”, partial pressure that is of component 2, vs. “x2”

is a straight line. Partial pressure is “x2” times P2sat. Of course “x2” was 1- “x1” times

P2sat. We have two straight lines so total pressure then is the pressure of 1 plus the

pressure of 2. It is the sum of these two straight lines, “x1” P1sat plus “x2” P2sat.The

concentration of mole fraction of “y” now in equilibrium once we have this pressure

vs. “x” line the actual mole fraction in the vapor phase, so the mole fraction of component

1 is “x1” P1sat just divided by the total pressure. This is the value of “x1” corresponding

value to “y1” in equilibrium is over here. This line is the “y1” value in equilibrium

which this “x1” value. It has to be at constant pressure and of course the whole plot is at

constant temperature. The corresponding temperature vs. “x1” and “y1” diagram. Here is an approximate

representation and the first thing to notice is that where this slope is positive for P

vs “x1” this T vs “x-y” have negative slopes. “y1” is greater than “x1” in this diagram

just like “y1” is greater than “x1” in this diagram. Component 1 has the higher saturation

pressure therefore it has a lower saturation temperature. Whereas on a pressure diagram

this is a straight line for Raoult’s Law neither one of these are straight lines. It is important

to understand the our normal convention is to pick component 1 in these plots as the

component with the higher saturation pressure. This is P1sat here, this is P2sat. That means

that component 1 has the lower saturation temperature at a given pressure and then for

an ideal solution “y1” is greater than “x1” in both of the diagrams.

gooooood , plz add subtitles

hello…Can you guys do videos on mass transfer, heat exchangers, reactors…..that would be really helpful

you sound like stan lee. :O are you stan lee? cause if your are stan lee. stan lee is cool!

Too fast.

Its a good video .. Do you have videos about the SOLID STRUCTURES ? (BCC,FCC..)

Yes, check out the Materials Science section under our channel

Do you have videos on Activity coefficients?

Yes, check them out under our thermodynamics playlist and/or visit our website for better organization by topics and textbooks

so the tottal vapour pressure af a mixture is a point on the yellow line??