CHMA10H3 Lecture Notes - Lecture 22: Infrared Spectroscopy, Vsepr Theory, Bond Length

• School: UTSC
• Department: Chemistry
• Course: CHMA10H3
• Professor: Marco Zimmer

Document Summary

Estimating reaction enthalpies: a reaction is exothermic when weak bonds break and strong bonds form, a reaction is endothermic when strong bonds break and weak bonds form. The distance between the nuclei of bonded atoms is called the bond length. Because the actual bond length depends on the other atoms around the bond, we often use the average bond length. Average for similar bonds from many compounds. Length: single bonds < double bonds < triple bonds. In general, the more e- two atoms share, the shorter the covalent bond: must be comparing bonds between like atoms. Generally, bond length decreases from left to right across period. Generally, bond length increases down the column. Generally, as bonds get longer, they also get weaker. Different vibrational motions have specific categories with energies corresponding to ns is in the infrared frequency range. Bond vibrations can be detected by ir absorption.