Green Flask Science

Chemistry simulations

Free interactive simulations for high school chemistry. Open one and use it with students today. No login, no download, and nothing is stored or sent.

UNIT 1

Matter and Measurement

Matter, measurement, density, and unit conversions.

UNIT 2

Atomic Structure

Atomic models, isotopes, light, and electrons.

UNIT 3

The Periodic Table

Organizing the table, families, valence electrons, and trends.

UNIT 4

Chemical Bonding

Ions, ionic and covalent bonds, shape, polarity, and forces.

UNIT 5

The Mole

Counting with the mole, mole conversions, and formulas.

UNIT 6

Chemical Reactions

Balancing, reaction types, and reaction calculations.

UNIT 7

Gases and States of Matter

Particles, heating curves, gas laws, and the ideal gas law.

UNIT 8

Solutions, Acids and Bases

Solubility, molarity, dilution, pH, and titration.

UNIT 9

Energy, Rates and Nuclear

Heat, reaction rates, equilibrium, and half-life.

Unit 1: Matter

3 free

States of Matter Lab

Heat and cool a substance and watch the particles speed up, spread out, and change state. Read the heating curve as it draws.

Matter Sorter

Sort items into elements, compounds, homogeneous mixtures, and heterogeneous mixtures. Build a streak and review what you missed.

Clue Hunters Virtual Lab

Run experiments, record the clues you see, and decide if a new substance formed. Physical change or chemical change?

Unit 1: Measurement

3 free

Measurement Reader

Read rulers, cylinders, and thermometers the way a scientist does: every certain digit plus one estimated digit.

Target Practice: Accuracy and Precision

Four lab workers weigh the same standard mass five times. Find the average and percent error, then label each worker.

Sig Fig Sprint

Count, round, and calculate with significant figures. Ten questions a round, with feedback that shows why.

Unit 1: Density and conversions

3 free

Density Lab

Weigh it, measure its volume, and use density to find out what a metal is made of. Then predict float or sink.

Density Column

Pour liquids and drop objects into a tall column. See how density decides where everything ends up.

Conversion Chain Builder

Build a chain of conversion tiles so the units cancel and only the unit you want is left.

Unit 2: Atomic models and particles

3 free

Build an Atom

Add and remove protons, neutrons, and electrons. Watch the element, charge, and mass number change.

Balloon Charge

Rub a balloon on a sweater or hair and watch electrons move. Then bring the balloon near a wall or paper bits.

Gold Foil Scatter

Fire alpha particles at a thin gold foil. Compare two models of the atom and count how the particles move.

Unit 2: Isotopes and atomic mass

3 free

Isotope Notation Trainer

Count particles, then write the hyphen name and the nuclear symbol for neutral atoms.

Isotope Mixer

Choose an element and move the percent abundance sliders. Watch the average atomic mass change.

Mass Spec Reader

Read the bars of a mass spectrum and calculate the average atomic mass.

Unit 2: Light and electrons

3 free

Light Spectrum Explorer

Slide the wavelength. Watch the color, the photon energy, and the wave change, then rank colors by energy.

Energy Level Jumps

Make a hydrogen electron jump between levels and see the photon that is given off or absorbed.

Electron Configuration Builder

Pick an element from 1 to 20 and see its energy levels, sublevels, configuration, and valence electrons.

Unit 3: Organizing the periodic table

3 free

Periodic Table Explorer

Click elements on the table and read each tile. Find the period, group, and type of every element.

Element Sorter

Drag twelve elements into metal, nonmetal, and metalloid bins, then check your sort.

Mystery Element Predictor

Use clues about a set of elements to predict the properties of a mystery element.

Unit 3: Families and valence electrons

3 free

Family Match-Up

Sort twenty element cards into the five families using valence electrons and behavior.

Valence Dot Builder

Pick an element, find its valence electrons, and place the dots around the symbol.

Ion Charge Predictor

Predict the charge an atom forms when it gains or loses electrons to fill its outer shell.

Unit 3: Periodic trends

3 free

Atomic Radius Trend

Move across a period and down a group. See how atom size changes and explain why.

Ionization Energy Race

Compare how much energy it takes to remove an electron from different elements.

Trend Detective

Use the trends to rank elements and solve trend puzzles.

Unit 4: Ions and ionic bonding

3 free

Ion Charge Finder

Click an element. Add or remove electrons on the outer shell until it is full. Read the charge.

Ionic Bond Builder

Pick a metal and a nonmetal. Transfer the electrons, then build the crystal.

Formula and Name Lab

Pick a cation and an anion. Watch the charges criss-cross, then read the formula and the name.

Unit 4: Covalent bonding

3 free

Bond Type Sorter

Read each formula and sort it into ionic or covalent.

Lewis Structure Builder

Pick a molecule. Count electrons, add bonds, add lone pairs, then check your structure.

Covalent Name Trainer

Practice naming covalent compounds and writing their formulas. Ten cards a round.

Unit 4: Shape, polarity, and forces

3 free

VSEPR Shape Explorer

Choose the number of bonds, then add lone pairs. Drag the picture to turn the molecule.

Polarity Tug-of-War

Pick two atoms, read the electronegativities, and see who pulls the shared pair harder.

IMF Boiling Point Lab

Decide if a molecule is polar and name its strongest force. Then see its boiling point.

Unit 5: Counting with the mole

3 free

Counting by Weighing

Use the mass of a small group to count a large pile without counting one by one.

Molar Mass Builder

Add atoms to build a formula and find its molar mass.

How Big Is a Mole?

Compare a mole to everyday amounts and get a feel for how large it is.

Unit 5: Mole conversions

3 free

Mole Map Trainer

Choose a challenge and follow the mole map between grams, moles, and particles.

Mole Balance

Add moles of different substances to a balance and log the masses.

Same Mass, Different Count

Predict which sample has more particles when the masses match, then check.

Unit 5: Composition and formulas

3 free

Percent Composition Pie

Build a pie chart of the mass percent of each element in a compound.

Empirical Formula Solver

Turn percent or mass data into a mole ratio and an empirical formula.

Hydrate Heater

Heat a hydrate, read the masses, and find how much water it holds.

Unit 6: Balancing equations

3 free

Mass Keeper

Run a reaction in a closed and an open container. Compare the mass before and after.

Balance It

Move the sliders and watch the atom counters on both sides until the equation balances.

Particle Matcher

Count atoms in particle pictures and match each picture to its balanced equation.

Unit 6: Types of reactions

3 free

Reaction Sorter

Sort ten equations into the five reaction types and look for the clues.

Product Predictor

Pick a reaction type and two reactants. Read the predicted products and write the equation.

Activity Series Explorer

Drop each metal into each solution to see which ones react. Rank the metals.

Unit 6: Reaction calculations

3 free

Mole Ratio Bridge

Put the four steps in order and convert from grams of one substance to grams of another.

Limiting Reactant Lab

Set the particles of each reactant and run the reaction until one runs out.

Yield Tracker

Enter a theoretical and an actual yield and calculate the percent yield.

Unit 7: Particles and states of matter

3 free

Temperature and Particle Speed

Pick a gas and slide the temperature from 200 K to 600 K. Read the average speed.

Solid, Liquid, Gas Lab

Pick a substance, slide the temperature, and watch the particles change state.

Build a Heating Curve

Start the heater and watch the heating curve build. Record points in a table.

Unit 7: The gas laws

3 free

Boyle's Law Pump

Slide the piston to change the volume and read the pressure at a constant temperature.

Charles's Law Balloon

Heat or cool a balloon and read the volume at a constant pressure.

Pressure and Temperature Tank

Heat a rigid tank and read how the pressure changes.

Unit 7: Ideal gases and mixtures

3 free

Ideal Gas Explorer

Move the sliders for moles, temperature, and volume and watch the pressure.

Gas Mixture Mixer

Add or remove moles of each gas. Read each partial pressure and the total.

One Mole at STP

Choose a gas and read its volume, molar mass, and density at STP.

Unit 8: Solutions and solubility

3 free

Dissolving Particles

Watch what happens to the particles when a solid dissolves in water.

Dissolving Speed

Change temperature, stirring, and particle size to see what speeds up dissolving.

Solubility Curves

Read a solubility curve and decide if a solution is saturated or unsaturated.

Unit 8: Molarity and dilution

3 free

Molarity Maker

Choose the moles and the volume to make a solution and calculate its molarity.

Dilution Station

Add water to a stock solution and see how the concentration changes.

Percent and ppm

Practice concentration in percent and parts per million.

Unit 8: Acids, bases, and pH

3 free

Acid and Base Particles

See the ions that acids and bases make in water.

pH Scale Explorer

Slide along the pH scale and compare common substances.

Titration Lab

Add base drop by drop to an acid and find the point where it is neutralized.

Unit 9: Energy in reactions

3 free

Specific Heat Race

Add the same heat to four samples and see which material warms up the most.

Coffee Cup Calorimeter

Dissolve a salt in water, read the temperature, and use q = m x c x change in T to find the heat.

Energy Diagram Builder

Slide the energy levels. Watch the activation energy and the sign of change in H. Add a catalyst to lower the peak.

Unit 9: Rates and equilibrium

3 free

Rate Factors Lab

Move two time points along the graph and find the average rate under cool, room, and warm conditions.

Collision Chamber

Change temperature, concentration, tablet form, and catalyst. Count the successful collisions.

Equilibrium Shifter

Stress a system and watch it shift to oppose the change and settle at a new equilibrium.

Unit 9: Nuclear chemistry

3 free

Half-Life Decay Lab

Let half-lives pass and watch the number of atoms left fall along a curve.

Nuclear Equation Balancer

Read a decay and pick the new nucleus. Check the mass numbers and atomic numbers.

Chain Reaction Lab

Lower the control rods and watch six generations of fission.

All nine Chemistry units are here. Use them free in your classroom.