DH_rxn = DH_{(bond breakage)} - DH_{(bond formation)}

Bond strengths in kcal/mole
C=O is 127.0, O=O is 59.6 , H-O is 102.4, H-C is 80.9,   C-C is 144.0
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1 Rank the following in order of increasing size.

a) Na⁺¹, K⁺, S^2-, Cl^-        _____ < ______ < _____ < ______

b) Li⁺, Na⁺, O^2-, S^2-, Cl^-, Br^-
____<____ < ____ < ____ < ____ < ____

2 The radius of Na⁺ is 1.16 Å and the radius of Cl^- is 1.67 Å. What is the density of NaCl? Note: NaCl forms a simple cubic crystal lattice.

3 What is the Lewis Dot structure for the following molecules and ions. Show all resonance structures.

CH₃CH₃

CO₂

O₂

CO₃^2-

N₂

BF₃

NO₂

PCl₅

4 From the table of bond energies at the top of the page, calculate the DH for the reaction of
C₂H₆ + O₂--->
 
 
 
 
 

5 Arrange the following in order of increasing bond polarity.

a) H-Se, P-Cl, O-Cl

b) H-Br, H-Cl, H-F

6 Arrange the following in order of increasing carbon-oxygen bond length.

a) CO, CO₂, CO₃^-2, CH₃OH

7 What is the bond order of each of the following carbon-oxygen bonds?