[sci0x]

Question
Nitric Oxide emissions is major cause of air pollution.

(a) How would you reduce NO emissions using the chemical equilibrium below:

N2(g) + O2(g) = 2NO(g)         DeltaH = 90.37 kJ mol^-1

[Mitch]

show work

[sci0x]

Well, i spose to reduce NO emissions you have to add something so its producing nitrogen only.

So maybe if you add H2, and this will convert the 2NO to N2

2H2 + 2NO = N2+ 2H2O

This right?

[sdekivit]

well you have to influence the equilibrium i assume, so what would your option then be ?

[sci0x]

Oh ok, Delta H is positive so forward reaction is endothermic.
Decrease temperature and less NO will form.

Correct?

[plu]

Absolutely

[Byrne]

Oh ok, Delta H is positive so forward reaction is endothermic.
Decrease temperature and less NO will form.

Correct?

Exactly.  The equation could also be written like this:

N2(g) + O2(g) + 90.37 kJ/mol <---> 2NO(g)

If you were to decrease the temperature, the system would shift to reduce the imposed change, according to Le Chaltelier's Principle.  So, if the temperature is decreased, the system will attempt to shift in the direction that will increase the tempreature of the system.  Since the forward reaction is enthothermic, the reaction will shift to the left, which is the exothermic direction, to raise its temperature.  Exothermic reactions result in a release of energy, which increases the system's temperature.  A shift to the left results in a decrease in the concentration of NO(g).