Consider the reaction:
2 HBr (g) → H₂ (g) + Br₂ (g)
b. In the first 25.0 s of this reaction, the concentration of HBr dropped from 0.600 M to 0.512 M. Calculate the average rate of the reaction during this time interval.

Verified step by step guidance

1. Determine the change in concentration of HBr: \( \Delta [\text{HBr}] = [\text{HBr}]_{\text{final}} - [\text{HBr}]_{\text{initial}} \).
2. Substitute the given concentrations into the equation: \( \Delta [\text{HBr}] = 0.512 \text{ M} - 0.600 \text{ M} \).
3. Calculate the change in time: \( \Delta t = 25.0 \text{ s} \).
4. Use the formula for average rate of reaction: \( \text{Average rate} = -\frac{\Delta [\text{HBr}]}{\Delta t} \).
5. Substitute the values of \( \Delta [\text{HBr}] \) and \( \Delta t \) into the rate equation to find the average rate.

Key Concepts

Reaction Rate

The reaction rate is a measure of how quickly reactants are converted into products in a chemical reaction. It is typically expressed as the change in concentration of a reactant or product per unit time. In this case, the average rate can be calculated by determining the change in concentration of HBr over the specified time interval.

Concentration Change

Concentration change refers to the difference in the amount of a substance in a given volume before and after a reaction occurs. For the reaction provided, the concentration of HBr decreases from 0.600 M to 0.512 M, indicating that HBr is being consumed as the reaction progresses. This change is essential for calculating the average rate of the reaction.

Average Rate Calculation

The average rate of a reaction can be calculated using the formula: average rate = -Δ[HBr]/Δt, where Δ[HBr] is the change in concentration of HBr and Δt is the change in time. In this scenario, the negative sign indicates that the concentration of HBr is decreasing. By substituting the values into this formula, one can determine the average rate of the reaction over the specified time interval.