H₂ and I₂ are combined in a flask and allowed to react according to the reaction: H₂(g) + I₂(g) ⇌ 2 HI(g) Examine the figures (sequential in time) and answer the questions: a. Which figure represents the point at which equilibrium is reached?

Verified step by step guidance

1. 1. The point at which equilibrium is reached in a chemical reaction is when the concentrations of the reactants and products stop changing. This means that the rate of the forward reaction (H2(g) + I2(g) -> 2 HI(g)) is equal to the rate of the reverse reaction (2 HI(g) -> H2(g) + I2(g)).
2. 2. To determine when equilibrium is reached, you would need to examine the figures and look for the point at which the concentrations of H2, I2, and HI stop changing. This is because at equilibrium, the concentrations of the reactants and products remain constant.
3. 3. If the figures are graphs of concentration versus time, the point at which the lines become horizontal (i.e., the slope of the line is zero) indicates that equilibrium has been reached. This is because the concentrations of the reactants and products are no longer changing.
4. 4. If the figures are images of the flask at different points in time, you would look for the point at which the appearance of the flask stops changing. This would indicate that the concentrations of the reactants and products are no longer changing, and thus equilibrium has been reached.
5. 5. Remember, reaching equilibrium does not necessarily mean that the concentrations of the reactants and products are equal. It simply means that their rates of reaction are equal, so the concentrations remain constant.

Key Concepts

Chemical Equilibrium

Chemical equilibrium occurs in a reversible reaction when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In the given reaction, H2 and I2 combine to form HI, and at equilibrium, the amount of H2 and I2 will remain unchanged as they are converted to HI and vice versa.

Dynamic Nature of Equilibrium

Equilibrium is dynamic, meaning that even though the concentrations of reactants and products remain constant, the reactions continue to occur in both directions. This concept emphasizes that molecules are still reacting, but the overall concentrations do not change, which is crucial for identifying the point of equilibrium in the reaction.

Le Chatelier's Principle

Le Chatelier's Principle states that if a system at equilibrium is disturbed by changes in concentration, temperature, or pressure, the system will adjust to counteract the disturbance and restore a new equilibrium. Understanding this principle helps predict how changes in conditions will affect the position of equilibrium in the reaction between H2, I2, and HI.