The "Chemistry page". Links, fun stuff and freeware!

JME Molecular Editor (also for Mac ;-))

The JME Molecular Editor (the picture below) is a Java applet which allows you to draw/edit molecules and reactions and to display molecules directly within an HTML page.

Click to try the JME Molecular Editor

To request JME send an email with subject "JME request" containing a short description of your project or intended JME use to: peter.ertl [at]

Build an atom

Build an atom out of protons, neutrons, and electrons, and see how the element, charge, and mass change. Then play a game to test your ideas!

Isotopes and Atomic Mass

Are all atoms of an element the same? How can you tell one isotope from another? Use the sim to learn about isotopes and how abundance relates to the average atomic mass of an element.

Build a Molecule

Starting from atoms, see how many molecules you can build. Collect your molecules and see them in 3D!

Balancing Chemical Equations

How do you know if a chemical equation is balanced? What can you change to balance an equation? Play a game to test your ideas!

Molecule Shapes

Explore molecule shapes by building molecules in 3D! How does molecule shape change with different numbers of bonds and electron pairs? Find out by adding single, double or triple bonds and lone pairs to the central atom. Then, compare the VSEPR model to real molecules!

Molecule Polarity

When is a molecule polar? Change the electronegativity of atoms in a molecule to see how it affects polarity. See how the molecule behaves in an electric field. Change the bond angle to see how shape affects polarity. See how it works for real molecules in 3D.


Watch your solution change color as you mix chemicals with water. Then check molarity with the concentration meter. What are all the ways you can change the concentration of your solution? Switch solutes to compare different chemicals and find out how concentrated you can go before you hit saturation!

Salt & Solubility

Add different salts to water, then watch them dissolve and achieve a dynamic equilibrium with solid precipitate. Compare the number of ions in solution for highly soluble NaCl to other slightly soluble salts. Relate the charges on ions to the number of ions in the formula of a salt. Calculate Ksp values.


What determines the concentration of a solution? Learn about the relationships between moles, liters, and molarity by adjusting the amount of solute and solution volume. Change solutes to compare different chemical compounds in water.

Acid-Base Solutions

How do strong and weak acids differ? Use lab tools on your computer to find out! Dip the paper or the probe into solution to measure the pH, or put in the electrodes to measure the conductivity. Then see how concentration and strength affect pH. Can a weak acid solution have the same pH as a strong acid solution?

pH Scale

Test the pH of things like coffee, spit, and soap to determine whether each is acidic, basic, or neutral. Visualize the relative number of hydroxide ions and hydronium ions in solution. Switch between logarithmic and linear scales. Investigate whether changing the volume or diluting with water affects the pH. Or you can design your own liquid!

Reactions & Rate

Explore what makes a reaction happen by colliding atoms and molecules. Design experiments with different reactions, concentrations, and temperatures. When are reactions reversible? What affects the rate of a reaction?

Chem scripts

Let the Scripts do your calculations. Click below


The drawing below is made in ChemSketch.

Download the ChemSketch file here

You  can download a freeware version of the program at

Molar weight calculator

One of my students has made a molar weight calculator for pc, mac and linux. It will calculate the total molar weight, when you press the buttons in the periodic table.

Click to try the Java version. If the screen is to small, then select: “ View --> Full Screen” from the menu bar.

You can download the pc, Mac or Linux version files here

Web sites with chemistry ;o)

The web site, where I have found the Jar files above is:

Periodic tables:

Web Elements



Formula collection

Net lex Formula

Visionary learning

Library of 3DMolecules


Kiros Chemical molekyles, Aarhus University

Toxnet- Varius toxic substances

Chemfinder  Data bases with chemical substances

Other pages

”Miljø og sundhed”   (danish site)

Chemland  (english site with animated tasks)

Department of Chemistry, Oxford University

Chem font

Video: Brainiac alkali metals, Explosions ;-)