how do I find the boiling point of a substance?

Question

if I know the substance has a vapor pressure of 40 torr at 673 C and 100 torr at 736 C?
please tell me the formulas!!!!!!!
the unit is K

Answer 1

Not positive about this, but you have two data points, so you can find the slope of the line and calculate temperature where vapor pressure is 760torr (1 atm). This, of course assumes the temperature/pressure behavior is linear. Also, since your highest temperature data point is only 100torr, you will be extrapolating a long ways beyond the known parameters so may be very inacurrate. If you do your calculations in C, remember to add 273 to get it in K. You can also get some boiling point data which might be usefull for distillation at reduced pressure; at a pressure of 100 torr the material will boil at 736 C. I hope this is of some help to you.