Learners solve word problems involving basic mechanical principles such as torque, horsepower, work, and power. Students who have problems with a particular word problem may try it again with a different set of numbers.

In this interactive object, learners examine how work is performed in foot-pounds by a hydraulic system that uses a pump and cylinder. A brief quiz completes the activity.

In this interactive and animated object, students distribute the valence electrons in simple covalent molecules with one central atom. Six rules are followed to show the bonding and nonbonding electrons in Lewis dot structures. The process is well illustrated with eight worked examples and two interactive practice problems.

Learners examine a table of common polyatomic ions. Eight examples are provided for practice.

Learners examine a table containing the names of common cations and anions.

Learners examine the method used to calculate the mass percent of an element in a compound. Three examples and one problem illustrate the method.

Learners view movie clips to determine the solubility of two ionic compounds. They also examine a solubility chart and predict the solubility of compounds.

Roman numerals are used to identify the charges on metal cations having multiple oxidation states. Five examples are provided for practice.

Learners complete an exercise to match chemical formulas with the names of binary compounds, tertiary compounds, and ions.