Expressing Concentrations Tutorial

This "map" shows the connections between units used in concentation calculations.

The Expressing Concentrations Tutorial is an interactive animation that defines solutions (solute + solvent), guides students in the creation of a Unit Map (shown), and presents several types of calculations that convert one concentration unit into another concentration unit. Chem21 animations provide a safe environment for learning . . . . students receive full credit when they correctly complete the animation - even with multiple restarts. This learning engagement is typically a lecture assignment, but can be assigned as a post-lab activity for labs like Oscillating Chemical Reaction, Molarity of Vinegar, etc.

Assigning the same tutorial in both lecture and lab is a great way to connect learning between the two courses.

In this tutorial . . . .

• students learn that solutions are comprised of a solute and a solvent.
• the Law of Conservation of Matter (CoM) provides the central relationship . . . .

  g Solute + g Solvent = g Solution

• Th CoM equation is "expanded" into the Soution Unit Map shown to the right.
• Students re-create this map by dragging / dropping units in the correct spot.
• The animation ends with a series of solution calculations where students use their map to express a given concentration in Molarity, molality, mass percent, ppm, mole fraction, or Normality.
• If the student enters an incorrect answer, they are shown the step-by-step solution, however, they must restart the animation.
• Students receive full credit when they correctly complete the animation - even with multiple restarts.