CHM 1301 Lecture Notes - Lecture 15: Bond Energy, Calorimetry, Ammonium Nitrate

• School: University of Ottawa
• Department: Chemistry
• Course: CHM 1301
• Professor: Mathew L

Document Summary

Linking bond energies and reaction energies v. 1. Ereaction = be bonds broken + be bonds formed. Be bonds formed = -(4 mol o-h x 460 kj/mol) = -1840 kj. Ereaction = (1365 kj) + (-1840 kj) = -475 kj. Linking bond energies and reaction energies v. 2. Bond energies can be used to estimate the energy changes that occurs in a chemical reaction: Ereaction = be bonds broken - be bonds formed. 2 h2 (g) + o2 (g) 2h2o (l) Be bonds broken = (2 mol h2 x 435 kj/mol) + (1 mol o2 x 495 kj/mol) Be bonds formed = (4 mol o-h x 460 kj/mol) = -1840 kj. Ereaction = (1365 kj) - (1840 kj) = -475 kj. A colorimeter can measure the heat flow that accompany a chemical reaction. Q calorimeter chemicals negative, reaction is exothermic chemicals = -q. If is q ( t calorimeter will rise)