About the Chemistry virtual labs

The inorganic lab

The general features of the inorganic simulation include 26 cations that can be added to test tubes in any combination, 11 reagents that can be added to the test tubes in any sequence and any number of times, necessary laboratory manipulations, a lab book for recording results and observations, and a stockroom for creating test tubes with known mixtures, generating practice unknowns, or retrieving instructor assigned unknowns. The simulation uses over 2,500 actual pictures to show the results of reactions and over 220 videos to show the different flame tests. In all, there are in excess of 10^16 possible outcomes for these simulations.

The quantum lab

The purpose of the quantum laboratory is to allow students to explore and better understand the foundational experiments that led to the development of atomic theory. In general, the laboratory consists of an optics table where a source, sample, modifier, and detector combination can be placed to perform different experiments. These devices are located in the stockroom and can be taken out of the stockroom and placed in various locations on the optics table. The emphasis here is to teach students to probe a sample (e.g., a gas, metal foil, two-slit screen, etc.) with a source (e.g., a laser, electron gun, alpha-particle source, etc.) and detect the outcome with a specific detector (e.g., a phosphor screen, spectrometer, etc.). Heat, electric fields, or magnetic fields can also be applied to modify an aspect of the experiment.

The gas lab

The gas experiments included in Virtual ChemLab allow students to explore and better understand the behavior of ideal gases, real gases, and van der Waals gases (a model real gas). The gases laboratory contains four experiments each of which includes the four variables used to describe a gas: pressure §, temperature (T), volume (V), and the number of moles (n). The four experiments differ by allowing one of these variables to be the dependent variable while the others are independent. The gases that can be used in these experiments include an ideal gas; a van der Waals gas with parameters that can be changed to represent any real gas; real gases including N2, CO2, CH4, H2O, NH3, and He; and eight ideal gases with different molecular weights that can be added to the experiments to form gas mixtures.

The titration lab

The virtual titration laboratory allows students to perform precise, quantitative titrations involving acid-base and electrochemical reactions. The available laboratory equipment consists of a 50 mL buret, 5, 10, and 25 mL pipets, graduated cylinders, beakers, a stir plate, a set of 8 acid-base indicators, a pH meter/voltmeter, a conductivity meter, and an analytical balance for weighing out solids. Acid-base titrations can be performed on any combination of mono-, di-, and tri-protic acids and mono-, di-, and tri-basic bases. The pH of these titrations can be monitored using a pH meter, an indicator, and a conductivity meter as a function of volume, and this data can be saved to an electronic lab book for later analysis. A smaller set of potentiometric titrations can also be performed. Systematic and random errors in the mass and volume measurements have been included in the simulation by introducing buoyancy errors in the mass weighings, volumetric errors in the glassware, and characteristic systematic and random errors in the pH/voltmeter and conductivity meter output.

The calorimetry lab

The calorimetry laboratory provides students with three different calorimeters that allow them to measure various thermodynamic processes including heats of combustion, heats of solution, heats of reaction, the heat capacity, and the heat of fusion of ice. The calorimeters provided in the simulations are a classic “coffee cup” calorimeter, a dewar flask (a better version of a coffee cup), and a bomb calorimeter. The calorimetric method used in each calorimeter is based on measuring the temperature change associated with the different thermodynamic processes. Students can choose from a wide selection of organic materials to measure the heats of combustion; salts to measure the heats of solution; acids, bases, oxidants, and reductants for heats of reaction; metals and alloys for heat capacity measurements; and ice for a melting process. Temperature versus time data can be graphed during the measurements and saved to the electronic lab book for later analysis.