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.
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.
Conversion Between Mass and Moles of an Element (Screencast)
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.
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.
Basic Elements of Dimensions Used in Engineering Drawings
In this interactive object, students explore the basic elements and common terms associated with dimensions and leaders. A quiz completes the activity.
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.
Simplifying Algebraic Fractions that Contain No Addition or Subtraction
In this highly interactive and animated object, learners follow a step-by-step process to reduce algebraic fractions, which contain no addition or subtraction, to their simplest, most elementary form. Immediate feedback is provided. This activity has audio content.
In this animated activity, students view the plastic pellets in a profile extrusion machine being melted as the temperature of the heating elements is elevated by a time proportioning control system.