Unique stoichiometric representation for computational thermochemistry
1Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA. ifishtik@wpi.edu
The Journal of Physical Chemistry. A
|January 10, 2012
Summary
This study introduces an exact solution for optimizing computational thermochemistry calculations. It presents a novel method using group additivity (GA) response reactions (RERs) for accurate enthalpy of formation evaluations.
Area of Science:
- Computational chemistry
- Quantum chemistry
- Thermochemistry
Background:
- Enthalpy of formation calculations often rely on minimal reference species in reaction schemes.
- When exceeding minimal species, computational thermochemistry faces optimization challenges.
Purpose of the Study:
- To present an exact and unique solution to the optimization problem in computational thermochemistry.
- To provide a stoichiometric interpretation of this solution.
Main Methods:
- Enumerating a finite and unique set of reactions.
- Utilizing group additivity (GA) response reactions (RERs).
Main Results:
- An exact and unique solution to the computational thermochemistry optimization problem is demonstrated.
- The solution is achieved by identifying specific GA response reactions (RERs).
Conclusions:
- The proposed method offers a definitive approach to solving optimization problems in thermochemistry.
- This facilitates more accurate evaluation of species' enthalpies of formation.
Related Concept Videos
02:55Thermochemical Equations
For a chemical reaction (the system) carried out at constant pressure – with the only work done caused by expansion or contraction – the enthalpy of reaction (also called the heat of reaction, ΔHrxn) is equal to the heat exchanged with the surroundings (qp).
01:16Thermal Sigmatropic Reactions: Overview
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
02:57Reaction Stoichiometry
A balanced chemical equation provides a great deal of information in a very succinct format. Chemical formulas provide the identities of the reactants and products involved in the chemical change, allowing classification of the reaction. Coefficients provide the relative numbers of these chemical species, allowing a quantitative assessment of the relationships between the amounts of substances consumed and produced by the reaction. These quantitative relationships are known as the reaction’s...
03:12Chemical Stoichiometry and Gases: Using Ideal Gas Law to Determine Moles
Chemical stoichiometry describes the quantitative relationships between reactants and products in chemical reactions.
02:26Chemical Reactions
A balanced chemical equation provides the information of chemical formulas of the reactants and products involved in the chemical change. A reaction’s stoichiometry helps predict how much of the reactant is needed to produce the desired amount of product, or in some cases, how much product will be formed from a specific amount of the reactant.
The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as stoichiometric amounts. However, in...
The relative amounts of reactants and products represented in a balanced chemical equation are often referred to as stoichiometric amounts. However, in...
01:19Chemical Reactions
A chemical reaction is a process by which the bonds in the atoms of substances are rearranged to generate new substances. Matter cannot be created or destroyed in a chemical reaction—the same type and number of atoms that make up the reactants are still present in the products. Merely, the rearrangement of chemical bonds produces new compounds.
Chemical Reactions Rearrange Atoms into New Substances
A chemical reaction takes starting materials—the reactants—and changes them into different...
Chemical Reactions Rearrange Atoms into New Substances
A chemical reaction takes starting materials—the reactants—and changes them into different...