5_60_lecture6

5_60_lecture6 - MIT OpenCourseWare http://ocw.mit.edu 5.60...

Info iconThis preview shows pages 1–3. 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
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: MIT OpenCourseWare http://ocw.mit.edu 5.60 Thermodynamics & Kinetics Spring 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms . 5.60 Spring 2008 Lecture #6 page 1 Thermochemistry Goal: To predict H for every reaction, even if it cannot be carried out in the laboratory The heat of reaction H rx is the H for the isothermal reaction at constant pressure. e.g. Fe 2 O 3 (s, T,p ) + 3H 2 (g, T,p ) = 2Fe(s, T,p ) + 3H 2 O( l , T,p ) ( , ) = 2 Fe ( T p ) + 3 H O 2 ( T p ) 3 H 2 ( T p , ) H 2 3 ( , ) H rx T p H , H , H Fe O T p [ H = H ( products ) H ( reactants ] ) rx We cannot know H values because enthalpy, like energy, is not measured on an absolute scale. We can only measure differences in enthalpy. Define a reference scale for enthalpy H (298.15K, 1 bar) 0 For every element in its most stable form at 1 bar and 298.15K H H 2 (g) ( 298.15 K ) = 0 e.g. The means 1 bar H C (graphite) (...
View Full Document

This note was uploaded on 07/31/2011 for the course CHM 170 taught by Professor Lemtayo during the Spring '11 term at MIT.

Page1 / 5

5_60_lecture6 - MIT OpenCourseWare http://ocw.mit.edu 5.60...

This preview shows document pages 1 - 3. Sign up to view the full document.

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