Chemical Reaction Mechanisms and Rates

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What is a chemical reaction mechanism?

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A chemical reaction mechanism is a step-by-step description of the pathway by which reactants are converted into products, detailing the individual elementary steps involved.

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Define the rate of a chemical reaction.

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The rate of a chemical reaction is the change in concentration of a reactant or product per unit time, often expressed in moles per liter per second (M/s).

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What factors affect the rate of a chemical reaction?

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Factors include concentration of reactants, temperature, surface area, and the presence of catalysts.

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What is the rate law expression?

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The rate law expression relates the rate of a reaction to the concentration of reactants, typically in the form: Rate = k[A]^m[B]^n, where k is the rate constant, and m and n are the orders of the reaction.

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How does increasing the concentration of a reactant affect the reaction rate?

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Increasing the concentration of a reactant generally increases the reaction rate, as there are more reactant particles available to collide and react.

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What is the order of a reaction?

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The order of a reaction is the sum of the powers of the concentration terms in the rate law expression, indicating how the rate is affected by the concentration of each reactant.

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Explain the role of a catalyst in a chemical reaction.

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A catalyst increases the rate of a chemical reaction by providing an alternative pathway with a lower activation energy, without being consumed in the reaction.

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What is activation energy?

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Activation energy is the minimum energy required for a chemical reaction to occur, allowing reactants to overcome the energy barrier to form products.

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How do temperature changes affect reaction rates?

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Increasing the temperature generally increases reaction rates, as it provides reactant molecules with more kinetic energy, leading to more frequent and effective collisions.

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What is the difference between a zero-order reaction and a first-order reaction?

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In a zero-order reaction, the rate is constant and independent of the concentration of reactants. In a first-order reaction, the rate is directly proportional to the concentration of one reactant.