Textbook 7E.1

[KatarinaReid_3H]

May someone explain parts a and b to me for this one? I am not quite sure of the concepts here.

[Emily Vu 1L]

We know that a catalyst's purpose is to lower the activation energy so the ability for a reaction to hit the threshold/pass the transition becomes easier in both directions. So, the presence of a catalyst increases the rate of a reaction for both the forward and reverse process.

For part (b), remember that enthalpy is a state function so regardless of the path - catalyzed or not - the delta H should stay the same.

[Anthony_3C]

I would like a add that the factors that influence the reaction rate constant k are the following: (which I learned from my brilliant high school chemistry teacher)

1. Activity (of the reactants themselves)
- for example, in the Alkali metal series, due to electronegativity differences, Fr>Cs>Rb>K>Na>Li for reaction rate. However, note that the rate of the reaction is
determined not by a single atom but the activity of every molecule.
- This also determines the value of the activation energy for each reaction
- Also note that the pattern of metals' Reaction RATE is not the same as the pattern in the Metal Activity Series, because reactivity is not only about the tendency of an element becoming an ion (as reflected in ionization energy and electronegativity). Reactivity takes into account the stability of the produced ion. Often reactions that take place in an aqueous solution takes into account the stability of the ion in water. (To restate this more clearly, The metal activity series only tells you how well a reducing agent IN AQEOUS solutions a metal is. This is determined by the reduction potential, which is related to SPONTANEITY. Yup we know that the Reduction Potential and the Gibbs free energy are related by G = nFE. THIS means that the metal activity series is influenced not only by electronegativity but also other factors like entropy which ultimately determine the STABILITY of the reaction products.

2.Temperature: T is high, k is high

3. Surface Area (Only for heterogenous reactions(containing reactants of different phases like gas and solid))
- for example: A solid cut into small pieces have larger surface area, and would react faster when thrown into a solution than an uncut solid.

4. presence of Catalyst or not

For a detailed explanation: this is a good website: https://courses.lumenlearning.com/introchem/chapter/factors-that-affect-reaction-rate/#:~:text=For%20gases%2C%20increasing%20pressure%20has,the%20solid's%20total%20surface%20area.

[Nico Medina]

I was wondering this too, thanks for the help!