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Ch.15 - Chemical Kinetics
Tro - Chemistry: A Molecular Approach 5th Edition
Tro5th EditionChemistry: A Molecular ApproachISBN: 9780134874371Not the one you use?Change textbook
All textbooksTro 5th EditionCh.15 - Chemical KineticsProblem 34d
Chapter 15, Problem 34d

Consider the reaction: 2 H2O2(aq) → 2 H2O(l ) + O2( g) The graph shows the concentration of H2O2 as a function of time. Use the graph to calculate each quantity: d. If the initial volume of the H2O2 is 1.5 L, what total amount of O2 (in moles) is formed in the first 50 s of reaction?

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1
Identify the initial concentration of H_2O_2 from the graph at time t = 0.
Determine the concentration of H_2O_2 at time t = 50 s from the graph.
Calculate the change in concentration of H_2O_2 over the 50 s period by subtracting the concentration at 50 s from the initial concentration.
Use the stoichiometry of the reaction: 2 H_2O_2 → 2 H_2O + O_2, to find the moles of O_2 produced. Note that for every 2 moles of H_2O_2 decomposed, 1 mole of O_2 is produced.
Convert the change in concentration of H_2O_2 to moles using the initial volume of the solution (1.5 L) and apply the stoichiometric ratio to find the moles of O_2 formed.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced based on balanced chemical equations. In this case, the stoichiometric coefficients indicate that 2 moles of H2O2 produce 1 mole of O2, which is essential for determining the amount of O2 formed from the given volume of H2O2.
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Molarity and Volume

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. To find the total amount of O2 produced, we first need to calculate the number of moles of H2O2 in the initial volume of 1.5 L. This involves multiplying the molarity of H2O2 by the volume in liters, which provides the necessary information to apply stoichiometry for the reaction.

Reaction Rate

The reaction rate refers to the speed at which reactants are converted into products in a chemical reaction. It can be influenced by various factors such as concentration, temperature, and catalysts. In this question, understanding the reaction rate is crucial for interpreting the graph of H2O2 concentration over time, as it helps determine how much H2O2 has reacted in the first 50 seconds, which directly affects the amount of O2 produced.
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