We've recently been developing automatically graded randomized virtual lab activities. These problems include random variables and support feedback for common student errors (for example, an automatic prompt when answers are off by orders of magnitude, suggesting that students check to see if they've converted mL to L for calculations.)
Follow the links below to access the activities. Each time the page loads, you will be given a new set of parameters. You will have 3 attempts to solve each problem before you are given the correct answer and asked to reload the problem and try again. Once you have entered the correct answer and completed the activity, you may print the page to be handed in to your teacher.
Like all of our efforts, this is a work in progress. If you have any suggestions for problems to add - or would like to customize one of these problems for your students - please contact us: .

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Stoichiometry, Density and Solution Concentration

Creating a stock solution - Create stock solutions from concentrated reagent bottles.
Metals Density Problem - Identify an unknown metal from its density.
Determining reactants and products in a solution of DNA - limiting reagents problem involving DNA.
Determine the concentration of unknown silver nitrate solution - limiting reagents problem.
Chemical remediation of arsenic - Determine the limiting reagent in a reaction involving the remediation of arsenic from drinking water.
Determining Stoichiometric Coefficients - Design and perform an experiment to determine a reaction, including its stoichiometric coefficients.
Mineral composition - Determine empirical formula from an elemental analysis.
Composition determination of a mixture - Determine the percent mass of mixture of two compounds.

Thermochemistry Problems

Coffee Problem - Create a solution of coffee with a desired temperature.
Camping Problem - Measure the enthalpy of a reaction and then create a solution warm enough to cook food.
Hot/Cold Pack Problem - Part 1: Determine the heat of solution for various salts.
Hot/Cold Pack Problem - Part 2: Using the information from part 1, design a hot/cold pack.

Acids and Bases

Unknown Acid Problem - Part 1: Perform an experiment to determine the pKa and concentration of an unknown acid.
Unknown Acid Problem - Part 2: Perform an experiment to determine the pKa and concentration of a second bottle of unknown acid.
Unknown Acid Problem - Part 3 Bonus: Perform an experiment to determine the concentrations of a mixture of two acids.

Analytical/Laboratory Technique

Determine the concentration of an unknown HCl solution using NaOH and solid KHP. (Adapted from a prelab exercise used at the University of British Columbia)
Determine the concentration of acetic acid in vinegar using a 0.110 M NaOH standard solution (Adapted from a prelab exercise used at Sinclair College)
Design an experiment to determine which of the two reagents, HCl or NaOH, is 10 times more concentrated than the other (Adapted from a prelab exercise used at the University of British Columbia)
Determine the concentration of an unknown KMnO₄ solution using solid sodium oxalate (Adapted from a prelab used at University of British Columbia)

Equilibrium and Solubility

Solubility and the Common Ion Effect - Determine the concentration of an unknown NaCl solution using the common ion effect.
Metal Ligand binding - Use silver chloride to determine the binding constant for a metal ligand complex.