# zHW: Multiple Independent Reactions

Formaldehyde is produced on an industrial scale by the incomplete oxidation of methanol in air. Principle by-products include formic acid, carbon dioxide, and carbon monoxide. Find a set of independent reactions for this reaction system.

## Contents

- Chemical Species
- Independent Reactions
- Displaying the Independent Reactions

## Chemical Species

The first step is to provide a list of all chemical species partcipating in the reaction system. Use molweight to verify correct entry of this list of species.

    species = { ...
        'CH3OH', ...     % Methanol
        'O2', ...        % Oxygen
        'CH2O', ...      % Formaldehyde
        'CHOOH', ...     % Formic Acid
        'CO', ...        % Carbon Monoxide
        'CO2', ...       % Carbon Dioxide
        'H2O'};          % Water

    molweight(species);

    Species                    Mol. Wt.
    -------                    --------
    CH3OH                         32.04
    O2                            32.00
    CH2O                          30.03
    CHOOH                         46.03
    CO                            28.01
    CO2                           44.01
    H2O                           18.02

## Independent Reactions

The rank of the stoichiometric matrix indicates the number of independent reactions that are possible.

    V = stoich(species);
    disp(' ');
    disp('V = ');
    disp(V);
    fprintf('\nNumber of Independent Reactions = %g\n',rank(V));

    V =
        -1     0     0     0
         0    -1     0     0
         0     0    -1     0
         0     0     0    -1
         3    -2     2     1
        -2     2    -1     0
         2     0     1     1

    Number of Independent Reactions = 4

## Displaying the Independent Reactions

    disp_reaction(V,species);

    CH3OH + 2 CO2 <=> 3 CO + 2 H2O
    O2 + 2 CO <=> 2 CO2
    CH2O + CO2 <=> 2 CO + H2O
    CHOOH <=> CO + H2O