Chapter 18, Problem 105A

Interpretation Introduction

Interpretation: The three things that increase the percent yield of the product are to be explained.

Concept Introduction: Le Chatelier's principle states that if a system in dynamic equilibrium is subjected to stress, the system will evolve in a way that reduces the stress.

Answer to Problem 105A

The three things that increase the percent yield of the product are high pressure, low temperature, and high concentration of reactants.

Explanation of Solution

Changes in the concentration of reactants or products, as well as changes in temperature and pressure, are stresses that drive off the equilibrium of a chemical system.

The reversible reaction for the formation of ammonia is given as follows:

  ${\text{N}}_{\text{2}}(g)+3{\text{H}}_{\text{2}}\left(g\right) \to 2{\text{NH}}_{\text{3}}\left(g\right)+\text{heat}$

Increasing the concentration of the reactants favors forward reaction which enables the product formation in high yield.

On increasing the pressure, the system will respond by favoring the reaction which produces fewer molecules.

As the temperature is lowered, the equilibrium shifts to the left, resulting in more liquid water.