MadSci Network: Chemistry

Re: Why is it not possible to calculate the enthalpy of formation of CO?

Date: Wed Mar 15 18:05:27 2000
Posted By: Raymond Cheong, Undergraduate, Chemical Engineering, University of Maryland
Area of science: Chemistry
ID: 952170076.Ch

Hi Catherine,

Typically, for a simple molecule like CO, you can look up the standard state enthalpy of formation in a table. If you have a chemistry textbook, there should be such a table in the back of the book. If not, NIST (National Institute of Standards and Technology) has a website with thermodynamic data (check the gas phase option). According to NIST, the DfH (CO) = -110.5 kJ/mol.

For simple molecules, the enthalpy of formation values are usually determined experimentally with very precise calorimetry measurements. Or, alternately, they could be calculated with Hess's Law, given (1) a reaction involving CO, (2) the overall change in enthalpy, and (3) the enthalpy of formation for all other molecules in the reaction. But, for a simple molecule like CO, the value above should be more accurate than the value from a direct calculation.

Your MAD Scientist,
Raymond Cheong

References: NIST Chemistry Webbook (NIST Standard Reference Database Number 69).

Current Queue | Current Queue for Chemistry | Chemistry archives

Try the links in the MadSci Library for more information on Chemistry.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2000. All rights reserved.