In this animated object, students examine what happens when electrons share molecules.

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.

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

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 animated object, learners examine the properties of the peptide bond and how the bond relates to the structure of hair.

In this animated lesson, learners read about the disulfide bond, the second strongest chemical bond in the hair. This bond can only be altered by chemicals.

In this animated object, learners examine how the heating or cooling steps in a manufacturing process work to control a chemical reaction.

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

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

This unit covers chemical safety from Unit 4.

Differentiate Pure Substances and Mixtures

Science Unit 1 End of Unit Test

Introduction