General Chemistry Laboratory Experiment Research Articles

Using Latex Balls and Acrylic Resin Plates To Investigate the Stacking Arrangement and Packing Efficiency of Metal Crystals

A high-school third-year or undergraduate first-semester general chemistry laboratory experiment introducing simple-cubic, face-centered cubic, body-centered cubic, and hexagonal closest packing unit cells is presented. Latex balls and acrylic resin plates are employed to make each atomic arrangement. The volume of the vacant space in each cell is measured by weighing water poured into the unit cell model, and the packing efficiency of each unit is obtained from the volume of vacant space. The observed values are compared with the theoretical calculations. Students can easily understand experimentally and theoretically that the packing efficiency of the face-centered cubic is the same as that of the hexagonal closest packing and significantly greater than that of the body-centered cubic. Moreover, they can understand the number of the neighboring atoms for any atom (coordination number) in each cell.

Demystifying the Chemistry Literature: Building Information Literacy in First-Year Chemistry Students through Student-Centered Learning and Experiment Design

This paper describes curriculum modules developed for first-year general chemistry laboratory courses that use scientific literature and creative experiment design to build information literacy in a student-centered learning environment. Two curriculum units are discussed: Exploring Scientific Literature and Design Your Own General Chemistry Laboratory Experiment. The modules sequentially develop and expand upon students’ chemical literacy, including the use of scientific literature to support experiment design. Student success is dependent on developing and using information literacy in service to critical thinking and practical analytical problem solving. A longitudinal study of students participating in this project surveyed self-assessed attitudes and beliefs. Initial findings suggest that introducing the scientific literature and building information literacy skills in first-year chemistry courses provide immediate and long-term benefits to student performance and engagement in the sciences. Course materials and assessment strategies used in the modules are provided as Supporting Information to this paper.

Removal of Aromatic Pollutant Surrogate from Water by Recyclable Magnetite-Activated Carbon Nanocomposite: An Experiment for General Chemistry

A general chemistry laboratory experiment using readily available chemicals is described to introduce college students to an exciting class of nanocomposite materials. In a one-step room temperature synthetic process, magnetite nanoparticles are embedded onto activated carbon matrix. The resultant nanocomposite has been shown to combine the adsorption ability of the activated carbon and the magnetic properties of the magnetite nanoparticles, enabling its application as a fast, effective, low-cost, and recyclable aromatic water pollutant adsorbent. This quality is illustrated by its rapid removal of the surrogate “pollutants”, made of several dyes in the Fisher universal indicator, within 2–3 min. A successful “pollutant” removal is indicated by the absence of the rainbow colors because of the presence of the “pollutants” in the “polluted” water when different quantities of an acid or a base are added. The nanocomposite’s reusability as the “pollutant” adsorbent is demonstrated after its used surface is regenerated using ethanol as the extracting solvent. The exercise allows students to (i) gain awareness of timely environmental issues; (ii) be exposed to the modern field of nanoscience; and (iii) appreciate the roles new and advanced materials play in keeping our water clean. Students have fun working in the lab and find the experience interesting and motivating. The experiment is also suitable for advanced high school students.

Headspace GC–MS Analysis of Halogenated Volatile Organic Compounds in Aqueous Samples: An Experiment for General Chemistry Laboratory

Analysis of halogenated volatile organic compounds (HVOCs) by GC–MS demonstrates the use of instrumentation in the environmental analysis of pollutant molecules and enhances student understanding of stable isotopes in nature. In this experiment, students separated and identified several HVOCs that have been implicated as industrial groundwater contaminants and deduced the isotopic content by analyzing the molecular ion region of the mass spectra. The HVOCs were analyzed by direct sampling of the headspace vapor over a dilute aqueous solution, which is designed to simulate a contaminated groundwater sample. The rapid headspace sampling and analysis allowed completion of the experiment by many lab classes per week. The impact of the lab was assessed using online surveys before and after the lab that queried student perceptions of their understanding, skills, and attitudes toward science and chemistry. The surveys showed noticeable gains in understanding and skills; however, few changes in attitudes were seen among students, the majority of whom already seemed committed to science and engineering careers and majors.

A Unit Cell Laboratory Experiment: Marbles, Magnets, and Stacking Arrangements

An undergraduate first-semester general chemistry laboratory experiment introducing face-centered, body-centered, and simple cubic unit cells is presented. Emphasis is placed on the stacking arrangement of solid spheres used to produce a particular unit cell. Marbles and spherical magnets are employed to prepare each stacking arrangement. Packing efficiency is calculated using simple measurements of marble or magnet diameters and the dimensions of the stacking arrangement. Edge effects are introduced. Packing efficiency is subsequently calculated for various metal samples employing density measurements and literature atomic radii values. The stacking arrangement for each metal and its corresponding unit cell are determined by comparing packing efficiency values. Estimated percent unoccupied space values for water and air are also determined.

The Use of Gas Chromatography and Mass Spectrometry To Introduce General Chemistry Students to Percent Mass and Atomic Mass Calculations

A general chemistry laboratory experiment is described that introduces students to instrumental analysis using gas chromatography−mass spectrometry (GC−MS), while simultaneously reinforcing the concepts of mass percent and the calculation of atomic mass. Working in small groups, students use the GC to separate and quantify the percent composition in a mixture of dichloromethane and chloroform dissolved in toluene by the injection of known quantities of each pure substance dissolved in toluene and the determination of the individual instrumental response factor. The relative abundances of the chlorine-35 and chlorine-37 isotopes can also be determined from several different groupings on the mass spectra of the compounds, allowing for the calculation of the atomic mass of chlorine. This collaborative-learning experiment enhances student understanding through the hands-on use of chemical instrumentation and helps to develop their problem solving skills in the analysis of several different types of experimental data.

Chemical Remediation of Nickel(II) Waste: A Laboratory Experiment for General Chemistry Students

This project involved developing a method to remediate large quantities of aqueous waste from a general chemistry laboratory experiment. Aqueous Ni(II) waste from a general chemistry laboratory experiment was converted into solid nickel hydroxide hydrate with a substantial decrease in waste volume. The remediation method was developed for a two-fold purpose: to provide procedures for removing nickel from an aqueous mixture and to serve as a template for the development of waste treatment experiments for pedagogical purposes.

Disulfiram, Metals, and Melanoma

A two-session general chemistry laboratory experiment is described concerning redox transformations of disulfiram, the disulfide of diethyldithiocarbamate (deDTC), related to its use in clinical trials for treatment of melanoma. In this laboratory, the students follow three different procedures to synthesize the complex Cu(deDTC)2 using sodium diethyldithiocarbamate, Na(deDTC)·3H2O; disulfiram, DSF; and an oxidized analogue, bis(dialkyliminium) tetrathiolane dication, (bitt-4)2+, as starting materials. The first method is essentially quantitative and has been used as an analytic method for trace metal detection as characterized by colorimetric analysis. The Zn, Ni, and Fe complexes are also synthesized and spectrally characterized. The latter two pathways involve redox disproportionation reactions of the sulfur compounds in which the stoichiometric ratios are obtained by balancing equations. Precipitation analysis is also used to qualitatively identify byproducts of the disproportionation reactions.

What Is That Colorless Solution? A Qualitative Analysis Laboratory for General Chemistry

A first-semester general chemistry laboratory experiment for college is described in which students carry out qualitative analysis to identify seven unknown colorless solutions. The experiment serves to correlate qualitative analysis with classification of reactions and can also be used in second-year or advanced-placement (AP) high school chemistry classes.

An Introduction to UV-Vis Spectroscopy Using Sunscreens

Two commercially available lotions that utilize only one active ingredient as a sunscreen were used to develop a general chemistry laboratory experiment involving the quantitative determination of the active component in each lotion by UV–vis spectroscopy. An open-ended group activity involving the qualitative assessment of the effectiveness of sunscreens containing multiple active ingredients by visual determination of fluorescence inhibition is also described.

A Colorful Investigation of a Diprotic Acid: A General Chemistry Laboratory Exercise

A general chemistry laboratory experiment that can be completed in a single laboratory period is described that familiarizes students with the acid—base chemistry of a diprotic acid and with the use of visible spectroscopy to determine species concentrations. This experiment is a modified version of a previously described laboratory exercise developed for an upper-division quantitative analysis course. Students work in teams and as a class to generate different ionization states of various highly absorbing dyes. Both spectroscopic and potentiometric (pH) data is collected using LabWorks II stations, but other inexpensive pH meters and visible spectrometers (e.g., Spec 20s) are suitable. A spreadsheet template is used to determine the percent composition of various ionization states of a diprotic acid and to determine the pKa values. Besides introducing students to fundamental tools and key chemical concepts, this laboratory is also inexpensive to operate and utilizes nontoxic, colorful solutions.

A Simple Protein Purification and Folding Experiment for General Chemistry Laboratory

Most general chemistry laboratories contain a surfeit of inorganic chemistry and little or no biochemistry. We describe a simple procedure for the crude purification of a chromoprotein suitable for a general chemistry laboratory. The protein, phycocyanin, is easy to purify and very stable. It contains a chromophore that can serve to report the integrity of the protein structure: the chromoprotein is dark blue when the protein is folded in its native conformation, and it turns a very pale blue when the protein is unfolded or denatured. The students must identify intermolecular forces present in the co-solvents added and determine their effect on the protein structure. The simplicity of the protein purification procedure will allow phycocyanin to be readily adopted in the general chemistry laboratory.

Integrated laboratory instruction using HiQ®

A HiQ® notebook was created to help students perform a multicomponent analysis using spectrophotometry for a general chemistry laboratory experiment. This interactive notebook featured a short tutorial on the methods necessary for this analysis as well as a step-by-step stimulation of the experiment. © 1998 National Instruments. Published by John Wiley & Sons, Inc. Lab Robotics and Automation 10: 81–82, 1998

Solubility and Ksp of calcium sulfate: a general chemistry laboratory experiment

The experiment shared in this note can be used to accompany lectures on solubility or chemical equilibrium.

The stoichiometry of hydrated copper sulfate. A general chemistry laboratory experiment

Students are provided with CuSO4.XH2O and asked to determine the % Cu, % SO4, and the number of water molecules in the hydrated salt using a cation-exchange resin coupled with gravimetric analysis.

Isopoly and heteropoly compounds: A general chemistry laboratory experiment

This procedure involves the preparation of isopoly and heteropoly salts and introduces the beginning student to liquid-liquid extraction, titration, ion exchange, conductance, and a variety of synthetic and analytical techniques.

A first general chemistry laboratory experiment

The goal of this introductory laboratory activity is to illustrate the difference between objective and subjective properties and the concept of significant figures.

Analysis for nitrite by evolution of nitrogen: A general chemistry laboratory experiment

This experiment involves analysis for the sodium nitrite content of a sodium nitrite-sodium chloride mixture by decomposition to nitrogen while heating in the presence of ammonium chloride solution.

Syntheses and titrations of unknown acids: A general chemistry laboratory experiment

Students prepare a solid unknown acid from an unknown starting material and then determine its equivalent weight by titration with a standard base.

A eutectic experiment for general chemistry laboratory

A eutectic experiment for general chemistry laboratory