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Ch.14 - Chemical Kinetics
Chapter 14, Problem 124a

Consider the reaction H2(g) + I2(g) → 2 HI(g). The reaction of a fixed amount of H2 and I2 is studied in a cylinder fitted with a movable piston. Indicate the effect of each of the following changes on the rate of the reaction. (a) An increase in temperature at constant volume

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Identify the relationship between temperature and reaction rate: According to the Arrhenius equation, an increase in temperature generally increases the reaction rate.
Understand the kinetic molecular theory: Higher temperatures increase the kinetic energy of molecules, leading to more frequent and energetic collisions.
Consider the effect of temperature on activation energy: With increased temperature, more molecules have the necessary energy to overcome the activation energy barrier.
Recognize that the reaction is taking place in a closed system with constant volume: This means that the concentration of reactants remains unchanged, so the effect of temperature is isolated.
Conclude that increasing the temperature at constant volume will increase the rate of the reaction due to more frequent and energetic collisions.

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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 refers to the speed at which reactants are converted into products in a chemical reaction. It is influenced by various factors, including concentration, temperature, and the presence of catalysts. Understanding how these factors affect the rate is crucial for predicting the outcome of a reaction under different conditions.
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Temperature and Kinetic Energy

Temperature is a measure of the average kinetic energy of particles in a substance. An increase in temperature typically results in higher kinetic energy, leading to more frequent and energetic collisions between reactant molecules. This increased collision frequency can enhance the rate of reaction, as more molecules have the energy required to overcome the activation energy barrier.
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Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust to counteract the change and restore a new equilibrium. In the context of the reaction H2(g) + I2(g) → 2 HI(g), increasing the temperature can shift the equilibrium position, potentially affecting the rate of formation of products and the overall reaction dynamics.
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