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Tutorials and Other Explanations

Measurements and Uncertainty

? Basic Math Techniques
S.I. units, significant figures, scientific notation, graphing...
? Dimensional Analysis
Several examples using dimensional analysis are worked to demonstrate the method. Practice problems are included.
? Measurements and Uncertainty
A tutorial for high school science students. A must for students when taking and reporting data.
? Numbers and Math Operations
Scientific notation, significant figures, dimensional analysis, temperature conversions...
? Scientific Measurements
Covers random and systematic errors, significant figures...
? Significant Figures
Practice problems determing the number of significant figures in a number.
? Significant Figures
Practice problems determining the number of significant figures when doing calculations.
? Uncertainty in Measurements
How uncertainty arises in length, temperature, and volume measurements. Treatment of significant figures included. Good start place to learn the concepts.

Atomic Structure

? Atomic Models
Changing 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 Page
Rotatable 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 Charge
General 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 Orbits
Moving 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 Atom
Basic 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 series
? Modern Atomic Theory
Rutherford'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 Model
Brief 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 Matter
Sections 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 Energy
Simple graphics are used to show the gas, liquid, and solid states of matter.
? Matter
Basics discussion of the physical and chemical properties of the states of matter.
? States of Matter
Gas, 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 Formulae
Sample calculations and practice problems involving empirical and molecular formulae.
? Determining Formula Mass
Examples of formula mass and percentage composition calculations plus practice problems.
? Mole Calculations
Mole calculations and practice problems.
? Preparation of Solutions
A 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 Calculations
Sample calculations and practice problems for determining solution concentrations.
? The Mole Table
Calculation of molecular weight, mole-to-gram calculation, gram-to-mole calculations...

Stoichiometry and Limiting Reactants

? Stoichiometry
Real-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.


? Chemistry of Rare Gases
Topics include the discovery of rare gases, synthesis of Xenon compounds, oxidation numbers for Xenon, rare gas compounds in lasers...
? Liquifying Oxygen
A 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.


? Balancing Chemical Equations
Balancing Equations by the Method of Oxidation-Reduction.
? Balancing Equations
Learning to balance equations by counting atoms plus practice problems.
? Writing Net Ionic Equations
In 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

? Bonding
Good summary of terms used to describe chemical bonds.
? Chemical Bonding
A discussion of covalent and ionic bonding.
? Chemical Bonding
Good visual representation of covalent and ionic bonding. Also good coverage of Lewis structures.
? Chemical Bonding
An alternate way of looking at chemical bonding... the electron-tunnelling model. Well done explanations and graphics.
? Chemical Bonds
Very basic discussion of covalent, ionic, polar covalent, and hydrogen bonds…
? Chemistry Review - Bonding
Review of covalent, ionic, van waals forces, and hydrogen bonding. The section on amino acids and hydrogen bonding is very useful.
? Hydrogen Bonding
Basic 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 Pairs
Discussion of conjugate acids and bases, acid and base strengths, leveling effect of water, pH of common acids and bases...
? Acid-Base/pH Tutorial
Text 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 Tutorial
This 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 pH
Visualizations of acid and neutral solutions. A description of the pH scale plus the pH of some common substances.
? The Fall of the Proton
Description of acid strength in terms of free energy. Also includes discussions of leveling effect, titrations, pH.
? pH Tutorial
The pH scale, acid-base considerations, equilibria, Lewis acids and bases, buffers, titration curves...

Structure and Intermolecular Forces

? Intermolecular Forces
Individual discussions of intermolecular forces, ion-dipole forces, dipole-dipole forces, and London forces. Well done. explanations...clear graphics.
? Intermolecular Forces
Short, one-page easy to read description of the origin of the forces of attraction between molecules with no overall charge.
? Molecular Geometry
Good summary of terms used to describe molecular geometries.


? Assigning Oxidation Numbers
The periodic table is shown with the common oxidation numbers of the elements.
? Determining Oxidation Numbers
The 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 Compounds
A short-hand way to represent compounds using symbols and oxidation numbers. Practice exercises.
? Oxidation Numbers
A 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-Reduction
Practical examples of redox reactions. Scroll down to Part IV - Everyday Examples...Bleaching agents, fuel combustion, corrosion...
? Redox Reactions
Good coverage of the basics. Sample problems with solutions for assigning oxidation numbers and for balancing chemical equations using the half-reaction method.


? Chemical Equilibrium
A series of slide presentations covering writing equilibriun expressions, intepreting equilibrium constants, predicting the direction of reaction, reaction quotients...


? Chemical Kinetics
University level treatment of rates of reaction, rate laws, rate constants, reaction order, molecularity, collision theory…


? Entropy and Poker
An interesting one page explanation of entropy using poker hands as illustrations.
? Entropy and a Box of Air
As 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 Summary
A 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 Mechanics
A 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 Mechanics
Text 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

? Isomers
Topics include: Cis/Trans isomers, chiral isomers, optical activity... Nice graphics.
? Aliphatic Amino Acids
A table of the aliphatic amino acids that includes structure, pka, formula weight, optical activity...chirality, melting points.
? Basic Organic Chemistry
Hydrocarbons, alcohols, Functional Groups, Carbohydrates, amino acids, basic organic reactions...
? Carbon Compounds
The structures of diamond and graphite are shown which can be used to explain the hardness of diamond while graphite breaks apart easily.
? Coordination Complexes
Topics include: coordination complexes, ligands, coordination numbers, Lewis acid-base approach to bonding in complexes.
? Enantiomers
Discussion of stereoisomism, chirality, enantiomers, factors necessary for chirality, examples...
? Hydrocarbons
Includes structure formulae of straight chain and branched hydrocarbons plus nomenclature coverage.
* IUPAC Nomenclature
The HTML reproduction of the "IUPAC Nomenclature of Organic Chemistry." Includes a search feature.
? Lab tips for Organic Students
Nothing 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 reactions
Page 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 Menu
Well 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 Basics
Basic discussion of molecular and structural formulae, chirality...
? Organic Reactions and Synthesis
Nice orderly review of functional group reactions.
? Resonance
A 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.


? Polymer of the Day
Structure, properties, and commercial applications of Kevlar, Nylon, polystyrene, polyethylene...
? Polymers
Website of macromolecules and polymer science. The section titled "Making Polymers" is particularly interesting.
? The Macrogalleria
Comprehensive 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.

Crystal Structure and Material Science

* Biocomposites - Design and Applications
Learn 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 Devices
? Crystal Growing Guide
A 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 Materials
Good general discussion and comparison of different classes of materials such as: metals, ceramics, semi-conductors, and polymers.
? Optical Birefringence
A 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 Solids
Topics include: properties of solids, lattice types, unit cells, close packing, structure of metallic elements, crystals…
? Systems of Crystals
A listing of the seven crystal systems with examples of each.

Nuclear Chemistry

? Introduction to Nuclear Physics
A 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 Nuclides
Click on an element in the pictured periodic table to get information regarding the stability and relative abundance of its known isotopes.
? Nuclear Science
Nuclear structure, radioactivity, alpha decay , beta decay, half-life, fusion, Fission, cosmic rays... Visualizations.
? U238 Decay
Radioactive 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 Tutorial
Includes 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 Problems
The 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 Spectra
Covers 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 Spectrometry
Includes 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 Basics
Theory, 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 Spectroscopy
Primarily text based treatment of NMR theory and Applications.
? Principles of IR Spectroscopy
Very 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 Spectroscopy
A 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 Spectroscopy
This 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 Compounds
MS, 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 20
Covers 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 Tutorial
Basic 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 NMR
Coverage of NMR from the very basic to reasonably complex. Includes sections on theory, hardware requirements, sample prep, C-13 NMR...


? An Introduction to Chromatography
Basic 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 Separations
A 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 Methods
Well written descriptions plus simple graphical illustrations for gas(GC), high performance(HPLC), liquid(LC), size exclusion(SEC), and tin layer chromatography(TLC).
? Gas Chromatography
A 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 Operation
A 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 Chromatography
A 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 Chromatography
A 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 Instrumentation
Books, 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 / Titration
? Analytical Methods of Analysis
An 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...
A short description of the coupling of gas chromatography with mass spectroscopy. Emphasis is on theory and the interpretation of mass spectra.
* Laboratory glassware Romanian company
We 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 customers
? UV-VIS Spectroscopy
A 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.


? Gases That Emit Light
An 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 Carbon
Topics include crystalline and amorphous forms of carbon, carbide reactions, oxides of carbon, carbon dioxide (CO2) in the atmosphere, chemistry of carbonates, fullerenes.
? Introduction to Electrochemistry
Covers redox reactions and balancing redox equations, electrochemical cells, cell voltages and batteries...
? Line Spectra
Begins 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 Light
Basic graphic and accompanying explanations of continuous, absorption, and emission spectra.
? The Chemistry of Water
A basic one page discussion of polarity, hydrogen bonding, and ionization with respect to water.
? Transition Metal Chemistry
Topics include: electron configurations, oxidation states...

Laboratory Topics

? Chemical Separations Techniques
Succinct 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 Recipes
Instructions for growing crystals of different sizes and colours using alum, potassium ferricyanide, copper acetate monohydrate, calcium copper acetate hexahydrate…
? Distillation
Distillation 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 Procedures
A 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 Molecules
Atoms, molecules, water, pH, isotopes, radioactive decay...
? Atoms and Molecules
Introductory discussion of matter, states of matter, structure of atoms, molecules and chemical reactions.
? Chem Team
A 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 Review
Review 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 Review
Maybe 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 Tutor
This 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 Tutorials
Interesting site of tutorials for beginning chemistry students. Includes dimensional analysis, balancing equations, Lewis dot structures, chemical bonding, acid-base chemistry...
? World Chemistry
A 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 Compounds
The classic demonstration of the presence of ions in aqueous solution when ionic compounds are dissolved in water.

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