What happens to the rate of the reaction when the concentrations of the reactants and products are changed in this equilibrium: N2(g) + H2(g) ⇌ NH3(g) + heat?

In the given equilibrium reaction, N2(g) + H2(g) ⇌ NH3(g) + heat, the rate of the reaction is influenced by the concentrations of the reactants and products. Here's how you can understand what happens to the rate of the reaction when the concentrations are changed:

1. Le Chatelier's Principle: According to Le Chatelier's Principle, if a system at equilibrium is subjected to a change, the system will respond in a way to partially counteract that change and restore equilibrium.

2. Effect of Concentration Changes: When the concentrations of the reactants or products are changed, it disrupts the equilibrium state. The system responds by shifting the reaction in the direction that reduces the disturbance.

- Increasing Reactant Concentrations: If the concentrations of N2(g) or H2(g) are increased, the system will respond by shifting the reaction to the right (forward direction) to consume some of the excess reactants. This will increase the rate of the forward reaction, leading to an increase in the rate of the overall reaction.

- Decreasing Reactant Concentrations: If the concentrations of N2(g) or H2(g) are decreased, the system will respond by shifting the reaction to the left (reverse direction) to compensate for the loss of reactants. This will increase the rate of the reverse reaction, resulting in a decrease in the rate of the overall reaction.

- Increasing Product Concentrations: If the concentration of NH3(g) is increased, the system will respond by shifting the reaction to the left (reverse direction) to decrease the excess product. This will increase the rate of the reverse reaction, leading to a decrease in the rate of the overall reaction.

- Decreasing Product Concentrations: If the concentration of NH3(g) is decreased, the system will respond by shifting the reaction to the right (forward direction) to produce more product. This will increase the rate of the forward reaction, resulting in an increase in the rate of the overall reaction.

In summary, changes in the concentrations of reactants and products can affect the equilibrium state, causing the system to shift in the direction that opposes the change. Consequently, the rate of the reaction will change accordingly.