High-temperature NO formation in air occurs through a thermal mechanism described by the following two reactions:

1. N2 + O2 → NO + N
kb1=3.42E+13

2. N + O2 → NO + O
Kb2=1.85E+9
By adding the oxygen dissociation reaction to this mechanism:

3. O2 + M → 2O + M
Kb3=4.00E+13
[M]=4.552E-8mol/cm^3

the time history of NO formation can be calculated at a constant temperature of 2500 K and a pressure of 1 atm.

Questions:

1. Develop a mechanism with separate reactions for forward and reverse directions.

2. Obtain one of the rate constants for each reaction from Appendix C and evaluate the other using thermodynamic data from Appendix A.

3. Plot the profiles of NO and O species as a function of time, as well as the sensitivity coefficients of NO with respect to each rate constant in the mechanism.

4. Estimate the approximate time required to reach the equilibrium concentration of NO.

5. Compare this time with the residence time in flames or combustion chambers.