Use this set of three thermodynamics demonstrations to both engage your students in a hands-on review and to test their understanding of this sometimes difficult yet fundamental topic.
- Entropy and Free Energy—Exothermic crystallization of sodium acetate trihydrate sparks a lively debate on spontaneity, free energy, enthalpy, and entropy.
- Hess’s Law—Two-part calorimetry demonstration provides data for reviewing the properties of state functions and performing H°, ΔS° and ΔG° calculations.
- Free Energy and Redox Reactions—Solve the Nernst equation for a copper concentration cell to demonstrate the relationship between free energy and electrode potential.
Enthalpy, heat of formation, Hess’s law, calorimetry, entropy, free energy. Time Required:
One class period
Materials Included in Kit:
Agar, 6 g
Copper metal strips, pkg/3
Copper(II) sulfate, 0.01 M, 250 mL
Copper(II) sulfate, 1M, 250 mL
Hydrochloric acid solution, 3 M, 250 mL
Potassium nitrate, 15 g
Sodium acetate, trihydrate, 250 g
Sodium bicarbonate, 10 g
Sodium carbonate, 10 g
Connector cord with alligator clips, 2
Cup, polystyrene, 8 oz, 4
Drying tube, flint glass, u-shaped, 150 mm
Foil barrier bag, 4½" x 3" x 12" x 4.3 mil nylon
Parafilm, 4" x 12"
Correlation to Next Generation Science Standards (NGSS)†
Science & Engineering Practices
Analyzing and interpreting data
Using mathematics and computational thinking
Constructing explanations and designing solutions
Disciplinary Core Ideas
MS-PS1.A: Structure and Properties of Matter
MS-PS1.B: Chemical Reactions
MS-PS3.A: Definitions of Energy
HS-PS1.A: Structure and Properties of Matter
HS-PS1.B: Chemical Reactions
Energy and matter
MS-PS1-4. Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.
HS-PS1-4. Develop a model to illustrate that the release or absorption of energy from a chemical reaction system depends upon the changes in total bond energy.