# Questions tagged [reaction-coordinate]

Questions related to abstract one-dimensional coordinates which represent progress along a reaction pathway.

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### Hessian Matrix and Physical directions: Potential Energy Surface

How do the eigenvectors of the Hessian Matrix for potential energy surface correspond directly to the physical directions of translation, rotation and vibration? I see that they might correspond to ...
23 views

### energy vs reaction coordinate diagram [closed]

To know the energy values-marked as ? and the coordinates-x,y for a given reaction ...
123 views

### Relationship between Gibbs free energy and potential energy (related to reaction coordinate diagrams)

For a rate law, the rate constant $k$ is given by the equation $$\ln k = \ln A - \frac{E_\mathrm{a}}{RT}\tag{1}$$ If $k_\mathrm{fwd}$ is the forward rate constant and $k_\mathrm{rev}$ is the reverse ...
175 views

### Y-axis of the reaction co-ordinate graph

In the graph of the reaction co-ordinate, is the $y$-axis that is used $∆H,$ $∆U$ or $∆G$?
5k views

### Law of Mass action VS Rate law [duplicate]

The Law of mass action has 2 parts - the equilibrium rate part & the reaction rate part. The "reaction rate part" states that rate of a reaction is directly proportional to the product of active ...
66 views

### AP Chem Question about Reaction Rate - Confused?

I found this question in the AP Chem book, and I understand why B is the answer (as the answer key says). However, I don't understand why D is not also correct. The question is: A multistep reaction ...
249 views

### Probability of the single molecule reaction to happen

I am trying to simulate the single particle second order reactions with known rate constants $k_1$ and $k_{-1}$ in Python. The point of this simulation is to fit the real experimental data to the ...
48 views

### Finding direction of the reaction using Affinity of the reaction

I encountered following reaction: $$\ce{CO + 1/2 O2 -> CO2}$$ I am provided with the composition of the various gases at $\pu{1000K}$ and am asked the direction of the reaction by finding the ...
47 views

### Is it possible to define the coordinates of an atom using other coordinates while optimizing in gaussian 16?

I know it is possible to fix the value of composite expressions using generalized internal coordinates (gic) in gaussian 16. But is it possible to assign that value to the coordinate of another atom. ...
217 views

### Is there any empirical upper limit for order of reaction?

I learned from one of my teachers that empirically reaction with order greater that 3 are never found. But, I am suspicious of the truth value of his claim. To add to my suspicion there is this paper ...
238 views

### Regarding the free energy requirements for reacting gases

Continued from my previous question here. With regards to the Boltzmann factor, I am confused on what type of terms we can substitute for E. I know kinetic energy is one, free energy as well, but ...
644 views

### Auto-catalysis Mechanism

I just read about the theory of auto-catalysis, and here's one thing which is sort of unclear to me: In this type of catalysis, one of the reaction product catalyses the reaction. For example, in ...
55 views

### Find reaction heat of a reaction [closed]

1) A(s)+O2(g) →Ao2; ΔH^0=-394kj/mol 2)AO(g)+ $\frac{1}{2}$O2(g) →AO2; ΔH^0=-283kj/mol 3)A(s)+ $\frac{1}{2}$O2(g) →AO(g); ΔH^0=-Xkj/mol Find the value of X? I want to know How to find this value.
6k views

### What does “reaction coordinate” mean? What does it mean when a reaction has TWO reaction coordinates?

I'm familiar with the concept of a reaction coordinate from high school chemistry as some generic conformational parameter that all of the intermediate states of a chemical reaction lie upon. Recently,...
2k views

### Why is law of mass action only applicable for elementary reaction?

Why can't we apply law of mass action for non-elementary reaction? Why does is vary with the rate law in case of non-elementary reactions?
56 views

### How to determine which normal mode leads to the transition state (numerically)? [closed]

I would like to get the normal mode of vibration which leads to the transition state. Do you know any software for this problem? If no, could you offer an algorithm to generate it? By the way, is ...
55 views

### Exothermic reaction [closed]

Please someone explain me the solution of this question.
87 views

2k views

### Reaction Pathways: What to do when IRC geometries are relaxed (optimized) and the energy changes significantly

The Story: Reaction pathways can be difficult things to deal with using electronic structure methods. Intrinsic reaction coordinates (IRCs) can be determined a number of ways (a discussion of these ...