Lecture22A - Lecture 22 1 Non-ideal Solutions; What makes a...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Lecture 22 1 Non-ideal Solutions; What makes a Solute? (24.5-9) Intermolecular interactions between different molecules usually are not the same as the interaction in pure liquids. Fig 24.9 For these three alcohols in water there are large deviations from ideal behavior as x ROH 0. Why? As R-group gets larger, less favorable water-ROH interaction, since R groups are hydrophobic, but as x ROH 1, interactions are basically ROH … ROH and we get ~pure material, ideal behavior: * ROH ROH P x P = alc Yet in the "non-ideal" region as 0, P . Why? ROH ROH x x O Alcohol is surrounded by water, so there is a uniform (but non-ideal) interaction between ROH and water: ( 29 * , , Henry's Law ROH H ROH ROH H ROH ROH P k x k P = = MeOH EtOH 1-proponol Lecture 22 2 * 1 1 1 1 1 1 1 ,1 In general: as 1, as 0, H x P x P x P x k O = O = In general for a two component system, Henry’s law behavior will be a consequence of Raoult’s law. 1 1 2 2 0 Gibbs-Duhem eqn. (T,P const) x d x d μ μ + = ( 29 , ln ln , 1,2 i i i i i i i T P P T RT P d RT dx i x μ μ μ 1 = + = = 1 ( 29 1 2 1 1 2 2 1 2 1 2 , , 1 2 1 2 1 2 , , ln ln 0 plug in ln ln T P T P T P T P P P x dx x dx dx dx x x P P x x x x 1 + = = - 1 1 = 1 Lecture 22 3 * 1 1 1 1 If 1 obeys Raoult's law, then as 1, x P x P O = * * 1 1 1 1 1 1 * 1 1 1 ln 1 as 1 x P P x x x x x P 1 = = 1 2 2 1 2 2 , ln so 1 as 1 or T P P x x x x 1 = 1 2 2 2 2 2...
View Full Document

This note was uploaded on 04/13/2008 for the course CHEM 444 taught by Professor Jameslis during the Spring '08 term at University of Illinois at Urbana–Champaign.

Page1 / 13

Lecture22A - Lecture 22 1 Non-ideal Solutions; What makes a...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online