Volume 5, Issue 3

Modeling of Ionization Energy of Elements Using Hartree-FockMethod: An Introduction to Computational Quantum Chemistry for Undergraduate Students
Original Research
The periodic properties of elements are central to the concept of chemistry and are deeply depending on the electron configuration of atoms. Among the common periodic properties such as atomic radii, electronegativity, electron affinity, the ionization energy of elements gives a clear trend in periodicity. Here, we present a classroom activity, mainly for undergraduate students, to simulate first ionization energy as an important periodic property of elements (up to xenon atom). A set of Hartree-Fock calculations were performed with Gaussian 03 suit of programs and the results have been compared with that of the experimental values. While comparing the experimental and calculated values, we have stressed the role of central-field approximation in the HF theory, important features of Slater type orbitals near the nucleus and the significance of electron correlation in multi-electron systems. Some suggestions for improvement of the results are also discussed.
World Journal of Chemical Education. 2017, 5(3), 112-119. DOI: 10.12691/wjce-5-3-6
Pub. Date: May 26, 2017
15843 Views3887 Downloads4 Likes
Synthesis of CuII-Nanocrystal Coordination Polymer by Microemulsion Method. Straightforward Experiment of Nanomaterial Synthesis for Science High School Students
Original Research
This work aims to demonstrate the experiment which was applied in the academic recreation club at science high school for learning about coordination chemistry and nanomaterial synthesis. Accordingly, the synthesis of the nanocrystal coordination polymer (NCP) by microemulsion method was employed as an example for this purpose. In this work, the general microemulsion (µEm) method was modified in order to provide the straightforward procedure for the synthesis of CuII-NCP for high school students. The results from transmission electron microscopy (TEM) and infrared spectroscopy (IR) were also discussed with the students.
World Journal of Chemical Education. 2017, 5(3), 107-111. DOI: 10.12691/wjce-5-3-5
Pub. Date: May 16, 2017
9151 Views3072 Downloads3 Likes
The Inhibition and Reactivation of Enzymatic Processes
Original Research
We present experiments that show the inhibition of the catalytic activity of the enzyme urease on the chemical degradation of urea with copper ions. In addition, we demonstrate the efficiency of the antidotes 2,3-dimercapto-1-propanesulfonic acid (DMPS, 2,3-bis(sulfanyl)propane-1-sulfonic acid) and 2,5-dimercapto-1,3,4-thiadiazole (DMTD) on reactivation of urease by complexation of copper.
World Journal of Chemical Education. 2017, 5(3), 102-106. DOI: 10.12691/wjce-5-3-4
Pub. Date: May 02, 2017
19288 Views3748 Downloads1 Likes
Thermochemistry of Acrylamide Polymerization: An Illustration of Auto-acceleration and Gel Effect
Original Research
Addition polymerization of alkenes is an exothermic process due to the relief of the bond strain from C-C double bonds (π bonds) in the monomer molecules. Control of exothermic reactions is crucial for preventing runaway reactions/explosions in the industrial setting. This experiment was designed for undergraduate students to demonstrate the exothermic nature of addition (chain-growth) polymerization and to estimate the enthalpy of polymerization using adiabatic calorimetry technique. Acrylamide (AAM) was polymerized using ammonium persulfate (APS) and Tetramethylethylenediamine (TMEDA) as redox initiators at room temperature. The concentration of AAM monomer was varied in the range of 5-25 wt. %, and the heat of polymerization was calculated from the recorded temperature rise (ΔT). The enthalpy of AAM polymerization (∆Hp) was estimated to be ≈ 16.5–19 kcal/ mole, depending on the monomer concentration. Enthalpy of polymerization was increased with increasing the monomer concentration due the auto-acceleration effect, which was clearly observed for solutions with AAM concentrations of ≥ 20 wt. %. The auto-acceleration phenomenon was identified from the fast and non-linear increase in the rate of temperature rise which reached a maximum of (0.5°C/ s) for solutions with AAM of 25 wt. %. For AAM concentrations of ≥ 20 wt. %, the auto-acceleration was accompanied by the polymer gelation (gel effect) due to the formation of the high molecular weight polyacrylamides.
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World Journal of Chemical Education. 2017, 5(3), 94-101. DOI: 10.12691/wjce-5-3-3
Pub. Date: April 21, 2017
23431 Views6229 Downloads1 Likes
Auto-Graded Chemical Equation Problems in Online Blackboard Assessments
Original Research
This article describes the development and implementation of auto-grade online chemical equation questions, created by using Fill in Multiple Blanks question options on the Blackboard Software. Five categories of questions other than multiple choice questions were effectively implemented in online assessments. This kind of questions may be used for large class online home works, tutorials, and proctored-quizzes.
World Journal of Chemical Education. 2017, 5(3), 91-93. DOI: 10.12691/wjce-5-3-2
Pub. Date: April 19, 2017
11644 Views2396 Downloads2 Likes
Preparation of Gel Alcohol Flavored with Essential Oils. An Employ of Laboratory Techniques in the Organic Chemistry Study
Original Research
The main aim of this work is to teach chemistry through a practical application. In it is described a chemical experiment for high school students. They learn fundamental concepts through the preparation of gel alcohol flavored. The experiment has four stages: search information, cultivation of aromatic plants, extraction of essential oils, and elaboration of gel alcohol. The hydro distillation technique was applied in order to obtain the corresponding essential oil. The aromatic plants used were cloves, lavender, rosemary, salvia and cedron. The essential oils were analyzed by gas chromatography. The experiment demonstrated to the students the application of chemistry for the preparation of personal care products making concepts more tangible than a simple reading.
World Journal of Chemical Education. 2017, 5(3), 86-90. DOI: 10.12691/wjce-5-3-1
Pub. Date: April 11, 2017
17760 Views4069 Downloads1 Likes