Learners identify combination, decomposition, displacement, and combustion types of redox reactions. They also watch a video clip that demonstrates the reaction of sodium and water.

In this screencast, learners examine the kinds of physical and chemical changes that occur in substances.

In this interactive object, learners determine the limiting reagent and the excess reagent in chemical reactions. Learners test their knowledge by solving three problems.

Learners use the coefficients in a balanced equation to develop the mole ratios of reactants and products involved in the reaction. Five interactive examples illustrate the method, and students test their knowledge by working four problems.

Learners calculate gas density from the standard molar volume and observe how the density increases with the increasing molecular weight of the gas.

Learners examine the meaning of theoretical yield, actual yield, and percent yield. They test their knowledge by solving two problems.

Learners read the definition of atomic weight and obtain the weights of elements by viewing the Periodic Table and charts that list atomic weights by name or symbol.

In this animated object, learners examine the formation of ester bonds in the synthesis of lipids using triglyceride biosynthesis as an example. Ester bond formation is described as a dehydration synthesis reaction.

Learners examine phase diagrams that show the phases of solid, liquid, and gas as well as the triple point and critical point.

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

Learners examine how five or six groups of electrons around a central atom cause the shape of the molecule to be trigonal bipyramidal, seesaw, T-shaped, linear, octahedral, square pyramidal, or square planar. Seven examples and three interactive questions are provided in this animated activity.

In this animated and interactive object, learners observe how two, three, or four groups of electrons around the central atom cause the shape of the molecule to be linear, trigonal planar, bent, tetrahedral, or pyramidal. Seven examples and eight interactive questions are provided.

In this animated and interactive object, learners examine kinetic and potential energy as well as the first law of thermodynamics and the flow of energy between a system and its surroundings. Students also answer questions about exothermic and endothermic reactions

The definition of an isotope is illustrated using the three isotopes of carbon. The three isotopes of hydrogen are discussed as exceptions.

In this animated object, learners examine how gas volume varies directly with absolute temperature (K at constant pressure). An example of a sample of gas at two conditions of volume and temperature is used to illustrate the law.

In this animated object, learners examine the formation of peptide bonds through dehydration synthesis.

In this brief object, learners examine the direct relationship between the volume of a gas sample and the number of moles of gas. A problem is presented so students can test their knowledge of Avogadro's Law.

Students practice identifying common elements from the periodic table by name or symbol.

In this interactive lesson, students examine the quantitative relationship between chemicals in a balanced mathematical equation.

Students read brief descriptions of atoms, molecules, elements, and compounds, and complete a matching exercise that pictures these particles and molecules as pieces of taffy.