Consider the reaction: H2(g) + Br2(g) → 2 HBr(g). The graph shows the concentration of Br2 as a function of time. a. Use the graph to calculate each quantity: (ii) the instantaneous rate of the reaction at 25 s.

Verified step by step guidance

1. insert step 1> Identify the section of the graph where the concentration of Br2 is changing around 25 seconds.
2. insert step 2> Determine the slope of the tangent line to the curve at 25 seconds. This slope represents the rate of change of Br2 concentration with respect to time.
3. insert step 3> Use the formula for the rate of reaction: Rate = -Δ[Br2]/Δt, where Δ[Br2] is the change in concentration of Br2 and Δt is the change in time.
4. insert step 4> Calculate the instantaneous rate by substituting the values obtained from the slope of the tangent line into the rate formula.
5. insert step 5> Remember that the rate of disappearance of Br2 is equal to the rate of formation of HBr divided by 2, due to the stoichiometry of the reaction.

Key Concepts

Instantaneous Rate of Reaction

The instantaneous rate of a reaction refers to the rate at which reactants are converted to products at a specific moment in time. It can be determined by analyzing the slope of the concentration vs. time graph at that particular time point. This slope represents the change in concentration of a reactant or product over a very short time interval, providing insight into the reaction's speed at that instant.

Concentration vs. Time Graph

A concentration vs. time graph visually represents how the concentration of reactants or products changes over time during a chemical reaction. The x-axis typically represents time, while the y-axis shows concentration. By examining the graph, one can identify trends, such as increases or decreases in concentration, and calculate rates of reaction at specific time points by determining the slope of the curve.

Stoichiometry of the Reaction

Stoichiometry involves the quantitative relationships between reactants and products in a chemical reaction, as described by the balanced chemical equation. In the reaction H2(g) + Br2(g) → 2 HBr(g), the stoichiometric coefficients indicate that one mole of H2 reacts with one mole of Br2 to produce two moles of HBr. Understanding stoichiometry is essential for calculating rates and concentrations, as it allows for the conversion between different species involved in the reaction.