Melting Point and Freezing Point
By Debbie McClinton, Dr. Miriam Douglass, Dr. Martin McClinton
Learners observe that the melting of a solid and the freezing of its liquid occur at the same temperature. The melting point is an intrinsic property and is used to identify a substance.
Taffy Atoms
By Eileen Bouchard
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.
How Pressure Changes Boiling Temperature
By Terry Bartelt, Terry Fleischman
Learners study the effect that pressure has on boiling temperatures. Once a liquid has reached a full boil, additional heat does not raise the liquid’s temperature; however, pressure can vary the boiling point of a liquid. A brief quiz completes the activity.
The Structure of an Atom
By Jill Larson
Students examine atomic structure and the octet rule.
Naming Compounds Containing Polyatomic Ions
Learners examine a table of common polyatomic ions. Eight examples are provided for practice.
Ions
Ions are electrically charged particles obtained from an atom or from a chemically bonded group of atoms by adding or removing electrons. Eight examples illustrate the number of protons, neutrons, and electrons in positive ions (cations) and in negative ions (anions).
Shapes of Simple Molecules - Part 2
By Dr. Miriam Douglass, Dr. Martin McClinton
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.
Oxidation Numbers
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.
Chemistry Math - Solving a Formula (Screencast)
By Laurel Maney
Students use algebra to rearrange formulas and solve for the missing volume, density, or mass quantity.
Chemical Bonds: The Hydrogen Bond
In this interactive object, students examine a type of chemical bond known as the "hydrogen bond."
Standard Molar Volume
By Dr. Miriam Douglass
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.
Gas Volume vs. Pressure (Boyle's Law)
Boyle's Law states that gas volume varies inversely with the pressure at constant temperature and is described by the equation PV = constant. An example of a sample of gas at two conditions of P and V is used to illustrate the law.
The Combined Gas Law
Learners combine Boyle's Law and Charles's Law to solve for the pressure, volume, and temperature of a gas sample under two sets of conditions.
Common Types of Oxidation-Reduction Reactions (Screencast)
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.
Ion Charges
In this interactive object, the learner practices identifying charges on ions.
Shapes of Simple Molecules - Part 1 (Screencast)
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.
The Limiting Reagent in Chemical Reactions
In this interactive object, learners determine the limiting reagent and the excess reagent in chemical reactions. Learners test their knowledge by solving three problems.
Calculating Formula Weight and Molecular Weight
In this interactive object, learners calculate formula and molecular weights by working through five examples and two problems.
The Kinetic Theory of Gases
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.
Percent Composition of Compounds (Screencast)
Learners examine the method used to calculate the mass percent of an element in a compound. Three examples and one problem illustrate the method.
Electromagnetic Radiation (Screencast)
In this animated and interactive object, learners examine the inverse proportionality of wavelength and frequency and their relationship to the speed of light.
Controlling pH
By Terry Bartelt
Learners view an animated presentation showing how the pH level of a cleaning solution is controlled in a closed-loop system in a manufacturing setting. A quiz completes the activity.
Molarity
Students solve a molarity problem in a drag and drop exercise.
Isotopes
The definition of an isotope is illustrated using the three isotopes of carbon. The three isotopes of hydrogen are discussed as exceptions.
Determining Empirical and Molecular Formulas (Screencast)
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.