Values of E a = 6.3 kJ/mol and A = 6.0⨉10 8 /(M s) have been measured for the bimolecular reaction: NO(g) + F 2 (g) → NOF(g) + F(g) (d) Why does the reaction have such a low activation energy?

Hello. In this problem, we are told an activation energy value of seven Children per mole was determined for the gas phase reaction shown below. We are asked to explain why the reaction has a low value for the activation energy. Let's begin by drawing a reaction profile diagram. So we have energy on the Y axis is a function of reaction progress on the X axis. We have the energy VR reactant to transition state and energy of our products. So this is our reacting energy, our products energy and energy at the transition state. So we are forming bonds and breaking bonds at the transition state. We are forming a bond between the hydrogen and chlorine and we are breaking a bond between the hydrogen and the mean activation energy then is the difference between the energy of our reactant and this transition state a lower activation energy, it means that we have a favorable reaction and the activation energy has to do with energy required to break bones so that we can go on to form new bones. So that means then we are breaking weaker bonds to form stronger bonds. So we are breaking weaker bonds between the hydrogen and the booming and forming stronger bonds between the hydrogen and the chlorine. So if we look at our answers that were given a says, the reaction has a low activation energy because the number of starting and product molecules are just equal again, activation energy has to do with energy associated with breaking bonds. So that we can go on to form new bonds. So it has doesn't have to do with the number of reactant or product. So we eliminate A B says reaction has a low activation energy because molecules involved are gasses. Again, it has to do with the energy associated with breaking bonds so that we can form new bonds. So it doesn't depend on the phase of our reactions to products. The next one says the reaction has low activation energy because hcl bond is weaker and easier to break as compared to the HBR bond. So a favorable reaction means that we'll be forming stronger bonds. That means then that we're forming a stronger bond between the hydrogen and chlorine rather than a weaker bond. So that eliminates. See the correct answer then, is d the reaction has the lower activation energy because the HBR bond is weaker and easier to break as compared to the hydrochloride bond. So again, the lower activation energy says, then that we are breaking this weaker bond and going on to form a stronger bond between the hydrogen, exploring. Thanks for watching. Hope this helps

Ch.14 - Chemical Kinetics

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McMurry 8th Edition

Ch.14 - Chemical Kinetics

Problem 137d

Chapter 14, Problem 137d

Values of E_a = 6.3 kJ/mol and A = 6.0⨉10⁸/(M s) have been measured for the bimolecular reaction: NO(g) + F₂(g) → NOF(g) + F(g) (d) Why does the reaction have such a low activation energy?

Verified step by step guidance

Understand that activation energy (E_a) is the minimum energy required for a reaction to occur. A low E_a means that the reactants can easily overcome the energy barrier to form products.

Consider the nature of the reactants and the reaction mechanism. NO and F_2 are both gases, which typically have higher kinetic energy and can collide more frequently and effectively, potentially lowering the activation energy.

Examine the bond strengths involved in the reaction. If the bonds being broken (e.g., F-F bond in F_2) are relatively weak compared to the bonds being formed (e.g., N-F bond in NOF), this can contribute to a lower activation energy.

Analyze the role of the pre-exponential factor (A) in the Arrhenius equation: k = A * e^(-E_a/RT). A high value of A suggests a high frequency of effective collisions, which can also contribute to a lower observed activation energy.

Consider any possible catalytic effects or reaction intermediates that might stabilize the transition state, thereby reducing the activation energy required for the reaction to proceed.

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Key Concepts

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

Activation Energy (Ea)

Activation energy is the minimum energy required for a chemical reaction to occur. It represents the energy barrier that reactants must overcome to transform into products. A low activation energy, like the 6.3 kJ/mol in this reaction, indicates that the reaction can proceed easily, often leading to faster reaction rates.

Arrhenius Equation

The Arrhenius equation relates the rate constant of a reaction to its activation energy and temperature. It is expressed as k = A * e^(-Ea/RT), where k is the rate constant, A is the pre-exponential factor, R is the gas constant, and T is the temperature in Kelvin. A high pre-exponential factor (A = 6.0⨉108/(M s)) suggests that the reaction has a high frequency of effective collisions, contributing to a faster reaction rate.

Bimolecular Reactions

Bimolecular reactions involve two reactant molecules colliding to form products. The rate of bimolecular reactions is typically dependent on the concentration of both reactants. In this case, the reaction between NO and F2 is bimolecular, and the low activation energy indicates that the collision between these two species is energetically favorable, facilitating the reaction.

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Values of E_a = 6.3 kJ/mol and A = 6.0⨉10⁸/(M s) have been measured for the bimolecular reaction: NO(g) + F₂(g) → NOF(g) + F(g) (a) Calculate the rate constant at 25 °C.

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The rate constant for the first-order decomposition of gaseous N₂O₅ to NO₂ and O₂ is 1.7 * 10-3 s-1 at 55 °C. (a) If 2.70 g of gaseous N₂O₅ is introduced into an evacuated 2.00 L container maintained at a constant temperature of 55 °C, what is the total pressure in the container after a reaction time of 13.0 minutes?

Values of Ea = 6.3 kJ/mol and A = 6.0⨉108/(M s) have been measured for the bimolecular reaction: NO(g) + F2(g) → NOF(g) + F(g) (d) Why does the reaction have such a low activation energy?

Verified video answer for a similar problem:

Key Concepts

Activation Energy (E<sub>a</sub>)

Arrhenius Equation

Bimolecular Reactions

Values of E_a = 6.3 kJ/mol and A = 6.0⨉10⁸/(M s) have been measured for the bimolecular reaction: NO(g) + F₂(g) → NOF(g) + F(g) (d) Why does the reaction have such a low activation energy?