zHW: Complete Combustion of Octane
Find the balanced reaction for the complete combuston of octane to carbon dioxide and water.
Octane
H H H H H H H H | | | | | | | | H - C - C - C - C - C - C - C - C - H | | | | | | | | H H H H H H H H
Contents
Chemical Formulas
Four species participate in the combustion reaction: octane, oxygen, carbon dioxide, and water. The first step is to construct a cell array with the formula for these species. Displaying the molecular weights is a convenient way to verify that the formulas are correctly entered.
species = {'CH3(CH2)6CH3','O2','CO2','H2O'}; molweight(species);
Species Mol. Wt. ------- -------- CH3(CH2)6CH3 114.23 O2 32.00 CO2 44.01 H2O 18.02
Stoichiometric Coefficients
Stoichiometric coefficients for the balanced reaction (or balanced reactions, if more than one independent reaction is possible) is computed with stoich. Reactants have a negative stoichiometric coefficient, products have positive coefficients.
V = stoich(species); disp(' '); disp('Stoichiometric Matrix V = '); disp(V);
Stoichiometric Matrix V = -1.0000 -12.5000 8.0000 9.0000
Display Balanced Reactions
The balanced reaction displayed as follows. Notice that stoichiometric coefficients are converted to integers for the displayed reaction. The balanced reaction is displayed in several different notations.
disp_reaction(V,species); disp_reaction(V,hillformula(species)); disp_reaction(V,{'Octane','Oxygen','Carbon Dioxide','Water'});
2 CH3(CH2)6CH3 + 25 O2 <=> 16 CO2 + 18 H2O 2 C8H18 + 25 O2 <=> 16 CO2 + 18 H2O 2 Octane + 25 Oxygen <=> 16 Carbon Dioxide + 18 Water