Question

Benzaldehyde, C6H5CHO}, has a normal boiling point of 179.0 C and a critical point at 422 C and 45.9 atm.

Using a phase diagram, estimate its vapor pressure at 125 Degrees

I'm directing it up again to Dr. Bob. (or anyone else who can help)

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If the boiling point (179) is at 1 atm, how would i solve it for 125? Do i subtract the two temperatures? The problem is very vague so I'm still lost

Answer 1

I mentioned the 179 only because it was in the original problem. It has nothing to do with the problem you are trying to solve; I thought it would give you some practice reading the graph. Look at the T axis, find 179, and that point on the P axis should be 1 atm or 760 mm Hg pressure. Now, for the problem, using the same liquid/vapor curve that gave you that number, find 125 on the T axis and read the vapor pressure on the P axis.

Answer 2

That's the problem, I have to make a diagram using only the data made available to me, and I have no idea how to make use of the critical point to solve this. If 179 is indeed equilvalent to 1 atm or 760 mm Hg, i can conclude that at 125 degrees its 0.1-0.9 atm, i just don't kno how to solve it like tihs.

Answer 3

"directing it up again to Dr. Bob".... Why??