Question

Indicate how each of the following will affect the equilibrium concentration of NH3 in the following reaction:

4NH3(g) + 5O2(g)reverse arrows 4NO(g) +6H2O (g) + 906 Kc

There are three possible answers for all questions

1- This will cause an increase in the equilibrium concentration of the reactant NH3

2- This will cause a decrease in the equilibrium concentration of the reactant NH3

3- This will not affect the equilibrium concentration of the reactant NH3

Part E- decrease the volume of the container

Part F- decrease the temperature of the reaction

Part G- remove some H2O(g)

Answer 1

Solution:-

This is a concept that states Le Chatelier's principle, which states that if you make changes with a chemical equilibrium, the equilibrium will change in such a way as to undo whatever you did. You should realize that the equilibrium will not shift all the way back, but it will shift to a new position that's closer to what it was previously.

Consider the following equilibrium:

a ⇌ b + c

At equilibrium, everything is ok. However, if you add some 'a' into mixture, the equilibrium will try to get rid of the 'a' that you have added. It does this by making more B and C. Likewise, if you remove some A, the reaction will tend to make more by causing B and C to react.

Energy also does the same thing. Exothermic reactions liberates energy, so you can consider them as a product. Endothermic reactions absorb energy, so they are reagent.

As a result, by increasing temperature in an exothermic reaction is like adding product, pushing the reaction toward the reagents.

Adding O2 means it will shift so as to use up O2. So it goes to the right.
Reducing H2O means it will try to make more H2O so it will shift to the right.