Textbook Question
Consider the reaction:
2 HBr (g) → H2 (g) + Br2 (g)
a. Express the rate of the reaction in terms of the change in concentration of each of the reactants and products.
Ch.14 - Chemical Kinetics
Chapter 14, Problem 25b
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 guidance1
Determine the change in concentration of HBr: \( \Delta [\text{HBr}] = [\text{HBr}]_{\text{final}} - [\text{HBr}]_{\text{initial}} \).
Substitute the given concentrations into the equation: \( \Delta [\text{HBr}] = 0.512 \text{ M} - 0.600 \text{ M} \).
Calculate the change in time: \( \Delta t = 25.0 \text{ s} \).
Use the formula for average rate of reaction: \( \text{Average rate} = -\frac{\Delta [\text{HBr}]}{\Delta t} \).
Substitute the values of \( \Delta [\text{HBr}] \) and \( \Delta t \) into the rate equation to find the average rate.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
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.
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Average Rate of Reaction
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.
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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.
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Related Practice
Textbook Question
Consider the reaction:
2 HBr (g) → H2 (g) + Br2 (g)
c. If the volume of the reaction vessel in part b was 1.50 L, what amount of Br2 (in moles) was formed during the first 15.0 s of the reaction?
Textbook Question
Consider the reaction: 2 N2O( g) → 2 N2(g) + O2(g) a. Express the rate of the reaction in terms of the change in concentration of each of the reactants and products.
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