Students use algebra to rearrange formulas and solve for the missing volume, density, or mass quantity.

Learners read about lab equipment and basic safety measures. In a quiz, they view photos and determine if the lab technicians pictured are using safe practices.

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.

In this screencast, students read about the basic organization and structure of the periodic table of elements. Students identify elements as belonging to a group, a period, or neither.

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

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

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

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

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.

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

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 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.

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

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.

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

In this animated activity, learners examine the terms "half-reaction," "oxidizing agent," and "reducing agent" and follow five interactive examples to balance equations for oxidation-reduction reactions. Three problems are provided as a self-check.

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

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 interactive object, students examine a type of chemical bond known as the "hydrogen bond."

Students read an explanation of chemical formulas in this animated activity. A quiz completes the object.