00:01
To answer this question, we need to use the form of the clausius clapperon equation, where the vapor pressure at the desired temperature, let's see, it wants to know at what temperature does benzene boil, so it's probably going to be easier to use the form.
00:26
The natural log of the ratio of the vapor pressures will be equal to negative delta h of vapor divided by r multiplied by 1 over the first kelvin temperature minus 1 over the second kelvin temperature.
00:51
So they tell us that the that benzene has a normal boiling point of 80 .1 degrees celsius so that's going to be one atmosphere of pressure.
01:11
The vapor pressure will equal atmospheric pressure, which is one atmosphere at its normal boiling point.
01:20
We'll call that p2.
01:24
And then they tell us, they want us to determine the temperature at which the vapor pressure is 675 millbar.
01:36
So it's probably going to be easier than to use bar here, which is more appropriate anyway.
01:43
Way, one bar, and they want us to calculate the temperature at which the vapor pressure is 0 .675 bar, or 675 millbar.
02:00
We'll set that equal to negative heat of vaporization, which they tell us is 30 .72 kilojoules per mole...