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Tutorials and Other Explanations
Measurements and Uncertainty
Basic Math TechniquesS.I. units, significant figures, scientific notation, graphing...Dimensional AnalysisSeveral examples using dimensional analysis are worked to demonstrate the method. Practice problems are included.Measurements and UncertaintyA tutorial for high school science students. A must for students when taking and reporting data.Numbers and Math OperationsScientific notation, significant figures, dimensional analysis, temperature conversions...Scientific MeasurementsCovers random and systematic errors, significant figures...Significant FiguresPractice problems determing the number of significant figures in a number.Significant FiguresPractice problems determining the number of significant figures when doing calculations.Uncertainty in MeasurementsHow uncertainty arises in length, temperature, and volume measurements. Treatment of significant figures included. Good start place to learn the concepts.
Atomic Structure
Atomic ModelsChanging understanding of the nature of the atom as seen through atomic models from Democritus, Dalton, Bohr, to the wave mechanical view.Atomic and Molecular Orbitals PageRotatable ball and stick or spacefill modes presented for viewing atomic and molecular orbitals alone with text descriptions for each. Separate sections cover hybrid orbitals and the molecular orbitals of benzene and diatomic nitrotrogen. Requires 300 kRas Mol plug-in so expect about a 6 minute load time.Effective Nuclear ChargeGeneral description of the way effective nuclear charge is determined along with on-site links to each element which includes effective nuclear charge for each energy level.Electron OrbitsMoving graphics are used to show the interaction between charged paticles. Student places a stationary or moving electron next to a proton and can see how the electron moves.Electronic Structure of the AtomBasic description how electron transitions within the atom result in absorption or emission of electromagnetic radiation, how to calculate the energy of transition, and how to convert this energy into frequency and wavelength. Helpful links to pages on site to a summary on quantum numbers and a nice graphic(gif) showing the electronic transitions for the hydrogen atom for the Lyman, Balmer and Paschen seriesModern Atomic TheoryRutherford's and Bohr's models of the atoms with respective limitations, electron transitions and radiation, the duality of electrons, Heisenberg, Schrodinger, wave mechanics, quantum mechanics, quantum numbers, effective nuclear charge...and all on three screen pages. A good study guide.The Atomic Modelhttp://pc65.frontier.osrhe.edu/HS/SCIENCE/pmodel.htmBrief descriptions of the various models of the atom with links to pages within the site with a more elaborate treatment of : The Greek Model, the Dalton Model, the Thomson Model, the Rutherford Model, the Bohr Model, the Quark Model... The Structure of MatterSections include: The Bohr model of hydrogen, quantum theory considerations, quantum numbers, and the shapes of atomic orbitals. The electronic stucture of the atoms is also related to oxidation states, ionization numbers, electron affinity, and atom/ionic size.
States of Matter
Matter and EnergySimple graphics are used to show the gas, liquid, and solid states of matter.MatterBasics discussion of the physical and chemical properties of the states of matter.States of MatterGas, liquid, and solid plus others which seem to be intermediate between commonly found substances and difficult to define or recognize. A listing of the various states of matter with a brief description for each is included. Supercritical fluids, plasma, liquid crystals....
Mole and Molecular Formula Calc.
Calculating Empirical FormulaeSample calculations and practice problems involving empirical and molecular formulae.Determining Formula MassExamples of formula mass and percentage composition calculations plus practice problems.Mole CalculationsMole calculations and practice problems.Preparation of SolutionsA guide for preparing laboratory solutions for which the calculations have been done. The relative amounts of solute and solvent are given for a variety of common laboratory solutions. See Links.Solution CalculationsSample calculations and practice problems for determining solution concentrations.The Mole TableCalculation of molecular weight, mole-to-gram calculation, gram-to-mole calculations...
Stoichiometry and Limiting Reactants
StoichiometryReal-time graphics show how reactants are used up and products are formed doing the course of a reaction. The limiting reactant concept is illustrated in the graphics.
Gases
Chemistry of Rare GasesTopics include the discovery of rare gases, synthesis of Xenon compounds, oxidation numbers for Xenon, rare gas compounds in lasers...Liquifying OxygenA classic experiment that involves gas laws, intermolecular forces, and paramagnetism with a nice, concise explanation of the paramagnetism of diatomic oxygen in terms of molecular orbital theory.
Equations
Balancing Chemical EquationsBalancing Equations by the Method of Oxidation-Reduction.Balancing EquationsLearning to balance equations by counting atoms plus practice problems.Writing Net Ionic EquationsIn describing reactions that occur in solution, it is often desirable to write the equation for the reaction in ionic form, indicating the ionic species that actually exist in solution.
Bonds and Bonding
BondingGood summary of terms used to describe chemical bonds.Chemical BondingA discussion of covalent and ionic bonding.Chemical BondingGood visual representation of covalent and ionic bonding. Also good coverage of Lewis structures.Chemical BondingAn alternate way of looking at chemical bonding... the electron-tunnelling model. Well done explanations and graphics.Chemical BondsVery basic discussion of covalent, ionic, polar covalent, and hydrogen bonds…Chemistry Review - BondingReview of covalent, ionic, van waals forces, and hydrogen bonding. The section on amino acids and hydrogen bonding is very useful.Hydrogen BondingBasic discussion of the electrostatic nature of hydrogen bonding. Nice plots of groups IV, V, and VI hydrides to show the effect of hydrogen bonding on boiling point.
Acids/Bases and pH
Acid-Base PairsDiscussion of conjugate acids and bases, acid and base strengths, leveling effect of water, pH of common acids and bases...Acid-Base/pH TutorialText sections on strong/weak acids, strong/weak bases, dissociation of water and the pH scale, salt solutions, buffers, common-ion effect, titration curves, solubility equilibria... Acid-base TutorialThis tutorial will allow you to explore the effect of changing reaction conditions on the acid-base equilibrium reactions of bromoacetic acid, a simple organic acid.Acids, Bases, and pHVisualizations of acid and neutral solutions. A description of the pH scale plus the pH of some common substances.The Fall of the ProtonDescription of acid strength in terms of free energy. Also includes discussions of leveling effect, titrations, pH.pH TutorialThe pH scale, acid-base considerations, equilibria, Lewis acids and bases, buffers, titration curves...
Structure and Intermolecular Forces
Intermolecular ForcesIndividual discussions of intermolecular forces, ion-dipole forces, dipole-dipole forces, and London forces. Well done. explanations...clear graphics.Intermolecular ForcesShort, one-page easy to read description of the origin of the forces of attraction between molecules with no overall charge.Molecular GeometryGood summary of terms used to describe molecular geometries.
Oxidation-Reduction
Assigning Oxidation NumbersThe periodic table is shown with the common oxidation numbers of the elements.Determining Oxidation NumbersThe determination of oxidation states based on knowing which elements can have only one oxidation state other than the elemental state and which elements are able to form more than one oxidation state other than the elemental state. Plus examples of balancing redox equations.Formulas of Binary CompoundsA short-hand way to represent compounds using symbols and oxidation numbers. Practice exercises.Oxidation NumbersA basic discussion of oxidation-reduction, oxidizing and reducing agents, rules for assigning oxidation numbers, balancing redox equations... Click on Equilibrium.Oxidation-Reduction (Redox)Balancing redox reactions, assigning oxidation numbers, lists of oxidizing/reducing agents, practice exercises.Oxidation-ReductionPractical examples of redox reactions. Scroll down to Part IV - Everyday Examples...Bleaching agents, fuel combustion, corrosion...Redox ReactionsGood coverage of the basics. Sample problems with solutions for assigning oxidation numbers and for balancing chemical equations using the half-reaction method.
Equilibrium
Chemical EquilibriumA series of slide presentations covering writing equilibriun expressions, intepreting equilibrium constants, predicting the direction of reaction, reaction quotients...
Kinetics
Chemical KineticsUniversity level treatment of rates of reaction, rate laws, rate constants, reaction order, molecularity, collision theory…
Thermodynamics
Entropy and PokerAn interesting one page explanation of entropy using poker hands as illustrations.Entropy and a Box of AirAs an example of entropy in action, consider the air in the building in which you're sitting. You assume the air is evenly distributed throughout it. If you go to the kitchen for a beverage, you don't stop to wonder "Gee, will there be air in the kitchen when I get there?" Why don't we have to worry about this?Entropy...a SummaryA 19 slide sequence of the most important aspects of the second law of thermodynamics. Includes slides on free energy, phase equilibrium, calculation of equilibrium constants…
Quantum Chemistry
Introduction to Quantum MechanicsA mathematical overview of quantum mechanics. Basic topics such as: emission spectra, wave-particle duality, quantum tunneling, Heisenburg Uncertainty Principle, spin, Schrodinger Wave Equation.Visual Quantum MechanicsText with only limited black/white graphics support but a good reference site for a beginning students. Mostly brief definitions/explantions of wavefunctions and probability
Organic Chemistry
IsomersTopics include: Cis/Trans isomers, chiral isomers, optical activity... Nice graphics.Aliphatic Amino AcidsA table of the aliphatic amino acids that includes structure, pka, formula weight, optical activity...chirality, melting points.Basic Organic ChemistryHydrocarbons, alcohols, Functional Groups, Carbohydrates, amino acids, basic organic reactions...Carbon CompoundsThe structures of diamond and graphite are shown which can be used to explain the hardness of diamond while graphite breaks apart easily.Coordination ComplexesTopics include: coordination complexes, ligands, coordination numbers, Lewis acid-base approach to bonding in complexes.EnantiomersDiscussion of stereoisomism, chirality, enantiomers, factors necessary for chirality, examples...HydrocarbonsIncludes structure formulae of straight chain and branched hydrocarbons plus nomenclature coverage.IUPAC NomenclatureThe HTML reproduction of the "IUPAC Nomenclature of Organic Chemistry." Includes a search feature.Lab tips for Organic StudentsNothing new here but knowing the contents of this tutorial with save time, increase yields, and improve safety in the organic lab.Mechanisms of simple substitution reactionsPage contains links to a few simple animations illustrating the Sn1 and Sn2 mechanism. Extremely basic but better than a static text example.Organic Chemistry Lecture Notes MenuWell written notes from a 30 lecture sequence that cover topics in beginning organic chemistry such as: alkanes, alkenes, alkynes, aromatics, caboxylic acids, alkyl halides,amines, designer drugs, ketones, aldehydes, nomenclature, mechanisms, stereochemistry, nucleophilic substitutions, NMR and IR spectra interpretation, etc.Organic Reactions BasicsBasic discussion of molecular and structural formulae, chirality...Organic Reactions and SynthesisNice orderly review of functional group reactions.ResonanceA guide for writing resonance structures. The nitrate anion is used as an example. Real time graphics are used to show the changing location of bonds in carbonate and sulfate anions.
Polymers
Polymer of the DayStructure, properties, and commercial applications of Kevlar, Nylon, polystyrene, polyethylene...PolymersWebsite of macromolecules and polymer science. The section titled "Making Polymers" is particularly interesting.The MacrogalleriaComprehensive coverage of polymers split into several sections (levels). Click on level two for information about uses, physical properties, and structure for a specific polymer. Click on level three for polymer basics such as: cross-linking, crystallinity and mechanical properties, copolymers, elastomers, thermoplastics, natural polymers... Level four covers preparation of specific classes of polymers. A great reference site for polymer information. Ultimate Polymer Science GuideAn excellent page which has got a great polymer science guide and some links for further reference...
Crystal Structure and Material Science
Biocomposites - Design and ApplicationsLearn more about Biocomposites - Design and Applications. Read the lectures on Natural Composites, Bioactive Ceramic Composites, Inert Ceramic Composites, Bone Cements, Dental Composites, Resorbable Polymer Matrices, Cast Materials and Cell seeded DevicesCrystal Growing GuideA review of a book on growing crytals that includes the procedure for growing crytals of potassium ferricyanide, copper acetate monohydrate, and calcium copper acetate hexahydrate. Also includes a very usedful FAQs list.MIT's World of MaterialsGood general discussion and comparison of different classes of materials such as: metals, ceramics, semi-conductors, and polymers.Optical BirefringenceA treatment on behavior of polarized light when it passes through isotropic or anisotropic solids, such as: glass, NaCl crystals, polymers, etc., replete with interactive Java applets to illustrate the important concepts.Structures of Inorganic SolidsTopics include: properties of solids, lattice types, unit cells, close packing, structure of metallic elements, crystals…Systems of CrystalsA listing of the seven crystal systems with examples of each.
Nuclear Chemistry
Introduction to Nuclear PhysicsA good place to begin to learn about the size and components of the nucleus, quarks, and the force(s) holding the nucleus together.Meet the NuclidesClick on an element in the pictured periodic table to get information regarding the stability and relative abundance of its known isotopes.Nuclear ScienceNuclear structure, radioactivity, alpha decay , beta decay, half-life, fusion, Fission, cosmic rays... Visualizations.U238 DecayRadioactive series for the stepwise decay of U238 to Pb206. The half-life and nature of the emission for each step is clearly outlined.
Spectroscopy and analysis
IR Spectroscopy TutorialIncludes the usual theory and characteristic functional group absorption frequencies but be sure to check out Section II: Sample Infrared Spectra. After choosing an unknown from the list in Section II, a molecular formula is displayed along with its IR spectrum. Correct interpretation of the IR spectrum will yield the correct structural formula for the unknown. The Interpret Spectra option explains the source of each absoprtion peak.Integrated Spectroscopy ProblemsThe 1H NMR, 13C NMR, infrared and mass spectra for an unknown compound is given along with its molecular formula. From this data a structure formula can be determined. Choose from a list of 10 unknowns.Introduction to IR SpectraCovers the basic theory of IR spectroscopy with supporting spectra. The best feature is the section on the effects of mass and hydrogen bonding on IR absorption frequency. To illustrate the mass effect the IR spectra of chloroform (CHCl3) and deuterochloroform (CDCl3) are overlayed. The disappearance of the peaks due to the C-H stretching and bending modes in the deuterated compound are clearly seen.Mass SpectrometryIncludes short explanations the uses and design of mass spectrometers. Very nice graphics illustrating how masses are separated using a mass spectrometer. Also, the mass spectrum of water and its interpretation.Mass Spectroscopy BasicsTheory, schematic of mass spectrometer, plus mass spectrum of toluene and its interpretation are included. Click on Return to Mass Spectrum Home Page for the mass spectra of five additional compounds.NMR SpectroscopyPrimarily text based treatment of NMR theory and Applications.Principles of IR SpectroscopyVery basic description of the theory absorption of IR radiation. Check it out for the animations of stretching and bending modes of vibration.Problems in NMR and IR SpectroscopyA great site to learn how to interprete IR and NMR spectra. Click on an unknown compound in the problem section and its molecular formula is displayed. Use the compound's spectra to determine its structural formula. The correct structure is given on request. Also, check out the WebSpectra IR Comparison link to see how small changes in structure affect IR absorption.Problems in NMR and IR SpectroscopyThis site provides introductions to NMR and IR spectroscopy plus a table of IR absorptions. Also included are practice problems using IR and NMR spectra at beginning, intermediate, and advanced levels of expertise.Spectral Database for Organic CompoundsMS, 13C NMR, 1H NMR, IR, and Raman spectra available when name and/or molecular formula of a sample is specified. Not the best spectra but the size of the database is impressive.Spectronic 20Covers theory and use of the Spec 20. Includes samples on cuvet selection, wavelength, selection, adjustment of 0% and 100% transmittance, measurement of absorbance, interpretation of results. Worth a look for the schematic of the Spec 20.Spectroscopy TutorialBasic coverage of IR and mass spectroscopy with sections on spectra interpretation, practice problems for each technique, and practice problems involving the intergrated use of both techniques.The Basics of NMRCoverage of NMR from the very basic to reasonably complex. Includes sections on theory, hardware requirements, sample prep, C-13 NMR...
Chromatography
An Introduction to ChromatographyBasic coverage from a pharmaceutical perspective with emphasis on amino acid separations. Succinct discussion of liquid chromatography techniques such as: ion exchange, gel filtration, affinity… Brief history of column and support development.Chemical SeparationsA series of slide presentations covering distillation, solvent extraction, chromatographic theory, gas chromatography (GC), liquid chromatography (LC), super critical liquid chromatography. Check out Types of Interactions under LC for illustrations of adsorption, partition, ion-exchange, and size exclusion processes.Chromatographic MethodsWell written descriptions plus simple graphical illustrations for gas(GC), high performance(HPLC), liquid(LC), size exclusion(SEC), and tin layer chromatography(TLC).Gas ChromatographyA description of the theory and of the experimental procedure used in gas chromatography (GC). Includes section on safety, proper use of a syringe, sample injection, calculation of GC peak areas, interpretation of data.. Useful graphics support the text.HPLC Theory and OperationA good reference source for chromatography. Theory of operation discussed for columns and packing, mobile phase, stationary phase, injectors, pumps, sample preparation… Read the text and do not be bothered by the accompanying equations.Paper ChromatographyA description of the theory and of the experimental procedure used in performing paper chromatography experiments. Includes sections on chamber and paper preparation, sample spotting techniques, development of the chromatogram, interpretation of data…Thin Layer ChromatographyA description of the theory and of the experimental procedure used in thin layer chromatography(TLC). Includes sections on plate preparation, spotting samples, plate development, calculating Rf values, and interpretation of data plus self checks as you go through the procedure. Well done, clear, easy to follow graphics.
Analytical Instrumentation
Analytical InstrumentationBooks, Journals, Software, and other Resources / Data Acquistion and Electronics / Data Handling / Diffraction / Electrochemistry / Gravimetry / Imaging / Mass Spectrometry / Materials & Surface Analysis / Optics / Sensors / Separations / Spectroscopy / Standards / Thermal Methods / TitrationAnalytical Methods of AnalysisAn excellent general purpose site. Basic tutorials of methods such as: atomic absorption, chromatography, electochemistry, spectroscopy, electrophoresis, diffraction, extraction, NMR ... Also coverage of theory and instrument components such as: Beer-Lambert Law, error propagation, optics, detectors, sources...GC/MSA short description of the coupling of gas chromatography with mass spectroscopy. Emphasis is on theory and the interpretation of mass spectra.Laboratory glassware Romanian companyWe are a production enterprise manufacturing laboratory glassware by burner blowing tehnology of the glass tubes.Our most important products are: various distillation apparatus, extraction apparatus, nitrogen determination apparatus, sulphur in oil determination apparatus, melting point termination apparatus, gas analysis apparatus.Optical Solutions, Inc.Optical Solutions, Inc. provides fiber optic filter photometers, diode array spectrophotometers and sample probes for use in the UV/VIS/NIR. The SMART PHOTOMETER technology, no-moving-parts designs and supporting software takes much of the guesswork out of long-term maintenance. Optical Solutions, Inc. is a preferred supplier to several of the largest chemical companies and include over half of the C&E News TOP 75 chemical manufacturers as customersUV-VIS SpectroscopyA discussion of the basics of uv-vis absorption spectrometry with expanded discussion via on-site links to related terms such as the Beer-Lambert Law. A schematic and picture of the single-beam Spectronic 20 spectrophotometer is included.
Spectra
Gases That Emit LightAn explanation of how gas discharge tubes work and why the colors of the emitted radiation depend on the identity of the gas and the construction of the lamp. Also includes a visible specrum and the line spectra of Hg, Ne, and Na for comparison purposes.Inorganic Chemistry of CarbonTopics include crystalline and amorphous forms of carbon, carbide reactions, oxides of carbon, carbon dioxide (CO2) in the atmosphere, chemistry of carbonates, fullerenes.Introduction to ElectrochemistryCovers redox reactions and balancing redox equations, electrochemical cells, cell voltages and batteries...Line SpectraBegins with the observation of the bright emission line spectra by Bunsen and the discovery of dark absorption lines in the solar spectrum. Be sure to click on emission and absorption in the text section on Bohr for simple but clear explanation of spectra.Spectra of LightBasic graphic and accompanying explanations of continuous, absorption, and emission spectra.The Chemistry of WaterA basic one page discussion of polarity, hydrogen bonding, and ionization with respect to water.Transition Metal ChemistryTopics include: electron configurations, oxidation states...
Laboratory Topics
Chemical Separations TechniquesSuccinct coverage of extraction, distillation, recrystallization, and chromatography techniques. The phase diagram used to explain the distillation process is the most detailed section is very helpful.Crystal RecipesInstructions for growing crystals of different sizes and colours using alum, potassium ferricyanide, copper acetate monohydrate, calcium copper acetate hexahydrate…DistillationDistillation from a chemical engineering perspective. Comphrensive text coverage with helpful graphics support. Includes sections on vaporization of pure components, vaporization of mixtures, batch distillation, and continuous distillation. Well done.Lab Equipment and ProceduresA comphrensive site which includes descriptions of how to use such equipment as burets, pipets, balances, barometers, magnetic stirrers, conductivity meters, pH meters ... plus performing procedures such as titrations, gravity and vacuun filtration, melting point determinations, reading a scale…
Tutorial Libraries
Atoms and MoleculesAtoms, molecules, water, pH, isotopes, radioactive decay...Atoms and MoleculesIntroductory discussion of matter, states of matter, structure of atoms, molecules and chemical reactions.Chem TeamA library of tutorials for high school chemistry students. Includes tutorials on equilibrium, the mole, nomenclature, colligative properties, significant figures, redox, stoichiometry, VSEPR, chemical bonding, acid-Base theory, kinetics, gas laws, periodic properties…Chemistry ReviewReview of chemical bonding including hydrogen bonding, Van der Waals bonds, hydrophobic interactions. Also included: pH, structual models, basic organic functional groups, review exercises.Chemistry Topics ReviewMaybe the most comphrensive list of general chemistry topics on the net. Just to mention a few of the ones that are not generally found: lattice energy, hybrid atomic orbitals, molecular orbital theory, free energy, the chemistry of nonmetals, radioactive decay, transition metal chemistry, valence bond theory, material sciences...Well worth investigating.Chemistry TutorThis site contains notes and self directed exercises designed to help students with the fundamental concepts of chemistry such as ideal gas law calculations, celsius/fahrenheit conversions, periodic table,grams/moles conversions....WHS Chemistry TutorialsInteresting site of tutorials for beginning chemistry students. Includes dimensional analysis, balancing equations, Lewis dot structures, chemical bonding, acid-base chemistry...World ChemistryA database of chemistry applets developed by the International School at Lepzig. Clear, well organized presentations of acid/base titrations, gas laws, LeChatelier's Principle, Maxwell-Boltzman speed distributions, kinetics, rate expressions, collision theory... Definitely worth a look. Some of the best new/continuing applet work on the web for high school chemistry students.
Odds and Ends
Solutions of Ionic CompoundsThe classic demonstration of the presence of ions in aqueous solution when ionic compounds are dissolved in water. |