00:01
To answer this question, we'll need to use a form of the clausius clapperon equation.
00:05
One form is the natural log of the vapor pressure the temperature we're interested in is equal to negative delta h vaporization in joules per kelvin mole divided by r multiplied by 1 over the temperature for which we want to calculate the vapor pressure minus 1 over the temperature for which we know a vapor pressure.
00:30
Pressure plus the natural log of the known vapor pressure.
00:39
So the natural log of the vapor pressure we need to calculate will be equal to, in this case, delta h vaporization is 39 .3 kilojoules per mole, so that'll be 39 ,300 joules per mole, divided by r, which is 8 .314, joules per kelvin mole.
01:02
Multiplied by 1 over the kelvin temperature for which we want to calculate the vapor pressure, that being 50 degrees celsius, 50 plus 273 .15 to get it into kelvin, gives us 3 .23 .15, and then minus 1 over the temperature for which we know the vapor pressure.
01:34
If its boiling point is 78 .3, then that means the vapor pressure.
01:41
If it's normal boiling point is 78 .3, then that means its vapor pressure will be equal to atmospheric pressure.
01:49
Normal means one atmosphere.
01:51
So we've got one atmosphere...