Sum: 2C6H14l 19O2 12CO2 14H2Og

1
Sum 2C6H14(l) 19O2 ? 12CO2 14H2O(g) DHo
-2DHfoC6H14 12DHfoCO2 14DHfo H2O(g)
-2(-167) 12(-394) 14(-242) -7782 kJ
or 3891 kJ/mol
2
CH123 Gen. Chem 1 12/3/01 Dr. J DH group
problems
The oxidation of long-chain carbon molecules
powers our society and our bodies. Consider the
following combustion reactions of two different
molecules each containing a 6C chain hexane
(C6H14) and glucose (C6H1206). Their structures
are shown to the right.

• Calculate the standard enthalpy (of combustion)
  of hexane, as depicted in the reaction below,
  given the following informationDHfo C6H14
  -167 kJ/mol DHfo CO2 -394 kJ/mol DHfo H2O
  -242 kJ/mol
• 2 C6H14(l) 19O2(g) ? 12CO2(g) 14H2O(g)

• Calculate the standard enthalpy of combustion of
  glucose, as depicted in the reaction below, given
  the following informationDHfo glc -1260
  kJ/mol DHfo CO2 -394 kJ/mol DHfo H2O -242
  kJ/mol
• C6H12O6 (s) 6O2(g) ? 6CO2(g) 6H2O(g)

• Compare the DHo combustion of each (kJ/mol).
  Which is higher? Would you predict this from
  their chemical structures? Explain.