userdata-paziras-Chem101-Chap_09A

Formacrystallinestructure netenergyreleased

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Unformatted text preview: st Ionization Energy of Na) Step 4: Formation of Cl (Cl atoms ® Cl ions) Cl (g) + e - Cl- (g) DH4 = –349 kJ/mol Na exothermic (Electron Affinity of Cl Step 5: Formation of NaCl(s) from ions + Na (g) + Cl- (g) Na+ Cl- (s) DH5 = –786 kJ/mol Na exothermic (Lattice Energy of NaCl = U) ­energy given off when ions form a crystalline structure Net Energy Released = + 108 kJ + 120 kJ + 496 kJ – 349 kJ – 786 kJ = – 411 kJ/mol 7 Chemistry 101 + Na (g) Chapter 9 + Cl(g) E. A. of Cl (–349 kJ/mol) I. E. of Na (+ 496 kJ/mol) + Na (g) + Cl (g) Na(g) + Cl(g) Dissociation of Cl2 (+ 120 kJ/mol) Na(g) + ½ Cl2(g) Sublimation of Na (+ 108 kJ/mol) Lattice Energy (–786 kJ/mol) Na(s) + ½ Cl2(g) DHf (NaCl) ­ 411 kJ/mol 8 Chemistry 101 Chapter 9 INTERPRETING THE ENERGETICS OF IONIC BONDING + · The Net Ionic React ion of the format ion of Na Cl- (s) is exothermic: Na(s) + + Na Cl (s) ½ Cl2(g) Higher Energy Less stable DHf = ­ 411 kJ/mol Lower Energy More stable NOTE: 1. The system’s energy i...
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This document was uploaded on 03/18/2014 for the course CHEM 101 at Los Angeles Mission College.

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