Can someone please help me and check-over my answers to these Chemistry problems?

Question

For the following problems, I had to refer to the reaction 2NH₃ (g) ↔ N₂ (g) + 3H₂ (g), and ΔH = 92.2 kJ.

1. What will be the effect on the concentration of H₂ if the temperature decreases?

A. H2 concentration will decrease.

B. H2 concentration will not change.

C. H2 concentration will increase, and pressure will decrease.

D. H2 concentration will not change, but ΔH will decrease.

E. H2 concentration will not change, but pressure will increase.

 

2. What will be the effect on the concentration of NH₃ if the pressure decreases?

A. NH3 concentration will decrease.

B. NH3 concentration will not change.

C. NH3 concentration will increase, and pressure will stay the same.

D. NH3 concentration will not change, but ΔH will decrease.

E. NH3 concentration will not change, but entropy will increase.

 

3. What will be the effect on N₂ if the concentration of NH₃ increases? _______

A. N2 concentration will decrease.

B. N2 concentration will not change.

C. N2 concentration will increase.

D. N2 concentration will not change, but ΔH will decrease.

E. N2 concentration will not change, but pressure will increase.

 

Answer 1

Hey Jesset, as this reaction is endothermic so increase in temperature will lead to an increase in the forward reaction and increase in forward reaction will lead to an increase i concentration of products and vice versa.

As regards the second question according to the Avogadro's law Volume is directly related to number of moles and inversely related to the pressure applied so, increasing the volume the reaction will move to a direction where number of moles are greater and increasing the pressure will have a reverse effect as in this equation the reaction has greater number of moles in product side so increasing volume or decreasing the pressure will increase the product concentration and hence reactant concentration will decrease.

In 3rd question, we follow this rule;

●removing something from product side or adding something on reactant side will increase forward reaction.

●removing something from reactant side or adding something on product side will increase the reverse reactant.

In this case we are increasing NH3 concentration i.e adding something on reactant side so reaction will move forward and concentration of product will increase.

Hope it will clear all your problems, do tell me if something left uncleared, thankyou.