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.
Heat of Fusion and Heat of Vaporization
Learners examine graphs and read that the heat of fusion is the heat energy absorbed by one mole of solid as it is converted to liquid, while the heat of vaporization is the heat energy absorbed by one mole of liquid as it is converted to gas.
Measuring Gas Pressure
By Dr. Miriam Douglass, Dr. Martin McClinton
Learners convert units used to designate pressure. Units for pressure are atm, mm Hg, torr, and pascal.
Gas Volume vs. Temperature (Charles's Law)
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.
Absolute Zero Temperature
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.
By Jill Larson
In this interactive object, the learner examines how pressure and volume relate to each other.
In this animated and interactive object, learners follow two rules to write unit conversion fractions.
Gas Volume and Molar Amount
By Dr. Miriam Douglass
In this brief object, learners examine the direct relationship between the volume of a gas sample and the number of moles of gas. A problem is presented so students can test their knowledge of Avogadro's Law.
Determining Empirical and Molecular Formulas
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.
Common Types of Oxidation-Reduction Reactions
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.
Standard Molar Volume
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.
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.
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.
The Formation of Ester Bonds in the Synthesis of Lipids
By Richard Wilkosz
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.
The Hydrogen Bond
In this interactive object, students examine a type of chemical bond known as the "hydrogen bond."
Pressure and Boyle's Law
Students examine standard pressure in this interactive object.
In this animated object, students examine the role equilibrium plays in everyday life. Formulas are presented in an interactive way.
In this interactive object, the learner practices identifying charges on ions.
A Biological Example of Water Solubility
In this animated object, students examine the role that the solubility of water plays in various biological functions.
Oxidation States of Ions
Learners examine the periodic table to identify metallic elements that have either fixed or variable oxidation states.
The Mole and Avogadro's Number
Learners examine how chemists use moles to "count" atoms by weight. Examples are given.
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 well-illustrated activity, learners examine the three types of intermolecular forces: dipole-dipole forces, London or Van der Waals forces, and the hydrogen bond. Two interactive questions are included.
Macroscale vs. Nanoscale
By Karen Nordell
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.
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.