Question

Consider the following reaction at equilibrium: 2NH₃ (g) ⇌ N₂ (g) + 3H₂ (g). Le Chatelier's principle predicts that the moles of H₂ in the reaction container will increase with ________?

1) an increase in temperature
2) a decrease in pressure
3) the addition of a catalyst
4) the removal of NH₃

Answer 1

The moles of H₂ in the reaction 2NH₃ (g) ⇌ N₂ (g) + 3H₂ (g) will increase by increasing temperature, decreasing pressure, or removing NH₃ according to Le Chatelier's principle. The correct options are 1, 2, and 4.

Step-by-step explanation:

Consider the equilibrium reaction 2NH₃ (g) ⇌ N₂ (g) + 3H₂ (g). Le Chatelier's principle provides insight into how the equilibrium will shift when changes occur in the reaction environment. The moles of H₂ will increase if:

• A temperature increase occurs, as the reaction is exothermic, and adding heat favors the endothermic direction (reverse reaction), which produces more hydrogen gas.
• Pressure is decreased, which favors the reaction that produces more moles of gas, in this case, the reverse reaction, thus increasing the amount of H₂.
• NH₃ is removed, which will shift the equilibrium to the right towards the products to replace NH₃ that was removed, producing more H₂ in the process.

However, the addition of a catalyst does not affect the position of the equilibrium; it only speeds up the reaction in both directions equally.