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.

Students identify the parts of a triple beam balance and practice measuring the mass of objects.

Atomic weights are used to convert the mass of a sample into the number of moles of the element in the sample and vice versa. Four examples are provided for practice.

Learners examine a table containing the names of common cations and anions. They then check their knowledge by answering a series of questions.

Students review the positions of metals, metalloids, and nonmetals in the Periodic Table and the general characteristics of each. A quiz completes the object.

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.

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

Students examine atomic structure and the octet rule.

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

Learners examine the method for calculating the atomic weight of copper from the natural percent composition of each of its two isotopes.

Learners view an explanation of how to read a graduated cylinder by measuring the lowest portion of the meniscus. A quiz completes the activity.

In this animated activity, learners examine what gases are composed of and how their particles interact. They also consider several assumptions that form the basis for the Kinetic Theory of Gases.

Students read an introduction to the lab equipment used to contain and dispense chemicals. A quiz completes the activity.

Learners examine how chemists use moles to "count" atoms by weight. Examples are given.

Learners view several movie clips that demonstrate the use of an indicator to follow the neutralization reaction that occurs when an acid and a base are mixed. Students test their knowledge in a series of questions. Immediate feedback is given.

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.

Students read different definitions of "acids" and "bases." In an interactive exercise, they identify if a substance is an acid or a base.

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

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.

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

Learners read definitions of atomic symbols, atomic numbers, and mass numbers and then answer questions about the number of neutrons, protons, and electrons in select elements.

In this interactive object, students examine how the volume and temperature of an ideal gas relate under conditions of constant pressure and quantity.

In this interactive object, learners calculate formula and molecular weights by working through five examples and two problems.

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.