CHEM 3303 - Supplementary Problems - Part 5

Isodesmic Equations

Question 1
For the following reactions, would you expect the product to be more or less thermodynamically stable than the reactants, based on average bond energies:

  1. SbCl3 + F2 → SbF3 + Cl2 [Solution]
  2. P(CH3)3 + S8 → S=P(CH3)3 [Solution]
  3. H2CO3 → CO2 + H2O [Solution]

Question 2
For the following reactions, which product would be expected to form (or neither):

  1. P4 + Cl2 → PCl3 or PCl5 ? [Solution]
  2. HCCH + Br2 → HBrCCBrH or HBr2CCBr2H ? [Solution]
  3. CN- + O2 → OCN- or CNO- (linear) ? [Solution]

CGMT Theory

Question 1
Would the following Compounds be expected to have planar or trans-bent geometries?

  1. H2CCH2 [Solution]
  2. H2SiSiH2 [Solution]
  3. H2CSiH2 [Solution]
FragmentSinglet-Triplet Gap
(kJ mol-1)
CH2-38
SiH288
    
BondBond Energy
(kJ mol-1)
CC(σ)346
SiSi(σ)222
CSi(σ)300
CC(π)295
SiSi(π)120
CSi(π)139 (est.)