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 follow a four-step process to determine the empirical formula of a compound from the masses of its constituent elements. The molecular formula is determined in a fifth step using the molecular weight of the compound.

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

In this animated object, learners examine the chemistry behind table salt.

Vapor pressure is the pressure exerted by molecules in the gas phase in equilibrium with a liquid or a solid. Two examples are used to illustrate vapor pressure: the drying of clothes and the evaporation of ice.

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

In this animated object, students are introduced to moles as a measurement.

In this animated object, students examine the role that the solubility of water plays in various biological functions.

In this well-illustrated object, learners examine the structures and properties of the four types of solids: molecular, metallic, ionic, and covalent network. Five interactive questions are provided.

In this animated and interactive object, learners follow two rules to write unit conversion fractions.

In this interactive and animated object, learners use solubility rules to predict when an insoluble ionic compound will precipitate in a double replacement reaction. Four step-by-step examples are given.

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

In this animated and interactive object, learners examine the inverse proportionality of wavelength and frequency and their relationship to the speed of light.

In this screencast we are introduced to the lab equipment used to contain and dispense chemicals.

In this screencast, we review the positions of metals, metalloids, and nonmetals in the Periodic Table and the general characteristics of each.

Learners examine how the boiling point increases with increasing pressure. An example from industry is given.

Learners view illustrations showing the direct dependence of the volume of a gas on temperature and consider the relationship between the Kelvin and Celsius temperature scales.

In this colorful, interactive object, learners examine how materials on the nanoscale compare with those on the macroscale. The focus is on the difference between macroscale and nanoscale gold in both color and melting point.

In this animated object, learners view hydrogen and hydroxide ions in a solution. A brief quiz on the basic principles of the term pH completes the activity.

In this interactive object, the learner examines how pressure and volume relate to each other.

In this animated object, students examine the role equilibrium plays in everyday life. Formulas are presented in an interactive way.

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.

Learners observe that the volume of one mole of any gas is 22.4 L at standard temperature and pressure. An illustration shows that only the mass of the molar volume differs with the identity of the gas.

Learners assign oxidation numbers to atoms in neutral compounds and in polyatomic ions. Six examples are worked through in detail, and three problems are provided.