Lecture 17 - Outline of Lecture 17: Chemical Equilibria...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Outline of Lecture 17: Chemical Equilibria Text: Atkins Chapter 9 (all) The general form of an equilibrium constant for the reaction: aA + bB = cC + dD is the following expression: K = (activity of C) c (activity of D) d /(activity of A) a (activity of B) b where the activities are determined at equilibrium. If not at equilibrium, then the ratio equals Q. The activity of an ideal gas is its partial pressure. The activity of a compound in a liquid or solution phase is essentially the same as its concentration. The activity of a solid is unity (the number 1). The activity of a nearly pure liquid is also 1. A high activity of a substance means that it is less stable toward reaction These principles are based on the contribution to the entropy that each kind of phase makes to a system. A gas at high pressure has less entropy (per mole) because it is less free. A liquid (or solute) at high concentration has less entropy because there are fewer distinguishable places to put each molecule in the sample without interchanging positions
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/29/2009 for the course ME 530.230 taught by Professor Katz during the Spring '09 term at Johns Hopkins.

Page1 / 2

Lecture 17 - Outline of Lecture 17: Chemical Equilibria...

This preview shows document pages 1 - 2. Sign up to view the full document.

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