Keto-enol tautomerization is paramount to understanding the mechanisms involved in many organic reactions and biochemical transformations. Isomerization of an enol to a carbonyl compound is typically introduced during the discussion of the acid-catalyzed electrophilic addition of water to alkynes. The tautomerization of carbonyl compounds to enol…

In this article we find the thermodynamics of some large N particles systems and some small N particles classical systems using micro canonical ensemble. Small N particle systems are seldom done in textbooks, since statistical mechanics(SM) systems work for large N systems. We show that small N systems will help the students to get an insight…

As simple and ubiquitous redox-active organic molecules, quinones participate in diverse electron transfer processes in chemistry and biological systems for energy transformation and signal transduction. We introduce here a practical exercise to study the redox potentials of benzoquinone and its two derivatives by combining the electrochemistry…

In this work, we venture to show how careful use of a program for quantum chemical calculations (such as VASP) may enrich teaching in solid-state chemistry and how principles of thermodynamics contribute to a validation of phase diagrams and reaction pathways using the quasiternary system Li[subscript 2]O-Al[subscript 2]O[subscript…

This study focuses on the experimental demonstration of the definition of kelvin using a triple point of water (TPW) cell and estimates the measurement uncertainty. The first part of this article is to construct the measurement setup and perform the measurements. The second stage is related with the calculation of uncertainty according to guides…

The fundamental principles and applications of thermodynamics and single-component phase equilibrium are used to explain and quantitatively analyze the operation and performance of the vapor-compression refrigerator (VCR). Carbon dioxide is used as the refrigerant. The four processes (or steps) that comprise the VCR refrigeration cycle are…

The design and operation of the vapor-absorption refrigerator (VAR) are described using the principles and tools typically covered in upper-division undergraduate physical chemistry courses. The objective is to enable students to understand in detail how this device works and how it compares with more typical vapor-compression refrigerators.…

A method for using electronic structure calculations to predict the standard molar enthalpy of combustion for hydrocarbons is presented. In this approach, simple geometry optimizations can be used to accurately compute the enthalpy of combustion within 3% of the experimental value using Hartree-Fock, MP2, or virtually any functional in density…

An introduction to the Quantum Chemistry Package (QCP), implemented in the computer algebra system Maple, is presented. The QCP combines sophisticated electronic structure methods and Maple's easy-to-use graphical interface to enable computation and visualization of the electronic energies and properties of molecules. Here we describe how the QCP…

A spreadsheet-based project is presented that is designed to enhance and expand student understanding of phase transition properties of pure water and ideal and nonideal (electrolyte) aqueous solutions. Using fundamental principles of classical and statistical thermodynamics, students calculate the melting and boiling points, the enthalpies and…

Surface modification has been considered as a fundamental item in upper-division undergraduate and master courses. Thus, the development of experiments regarding processes and characterization of surface-modification phenomena is highly desired. In this article, we propose an electrochemical and computational study of widely used…

Determination of thermostability of enzymes is of prime importance for their successful industrial applications and, yet, the published data has often been incompletely analyzed to assess the suitability of enzymes. It is possible to determine meaningful thermostability parameters from the routinely acquired data through a straightforward method…

Activation energies form an energy barrier to a chemical reaction taking place. Simple collision theory, i.e. that particles need to collide to react, would suggest that activation energy is the energy needed to overcome a coulombic barrier provided by the negatively charged electrons contained within energy shells surrounding an atomic nucleus.…

The second law of thermodynamics has various formulations. There is the "Clausius formulation," which can be stated in a very intuitive way: "No process is possible whose sole result is the transfer of heat from a cooler to a hotter body." There is also the "Kelvin-Plank principle," which states that "no cyclic…

G, G°, [delta][subscript r]G, [delta][subscript r]G°, [delta]G, and [delta]G° are essential quantities to master the chemical equilibrium. Although the number of publications devoted to explaining these items is extremely high, it seems that they do not produce the desired effect because some articles and textbooks are still being written with…