For the reaction of nitrogen gas and hydrogen gas to make methane below, what stresses would shift the equilibrium to the left toward the reactants? N2(g) + 3 H2(g) ⇌ 2 NH3(g) + Energy

1) Adding more NH₃

2) Raising the temperature of the reaction

Explanation:

To answer the question, we are to note that the reaction is a reversible reaction, hence to shift the equilibrium to the left we would alter the equilibrium conditions as follows;

1) Adding more of the product NH₃ to the reaction at equilibrium

Increasing the quantity of products will force the concentration of the reactant product combination at equilibrium to readjust forming more of the reactant, because, for example, at equilibrium we have one mole of N₂ combining with 3 moles of H₂ forming 2 moles of NH₃. If the NH₃ is increased to 4 moles then there will be more H₂ and N₂ formed to regain equilibrium

2) Increasing the reaction temperature

It is also observed that the reaction produces energy, that the the energy of the product is less than those of the reactant. Therefore, to shift the equilibrium to the left, that is towards the reactants, we have to increase the temperature of the reaction so that there will be enough energy for the formation of the higher energy reactants.