Exploring Entropy and Gibbs Free Energy in AP Chemistry

This AP Chemistry lesson, led by Michael Faribault, covers Unit 9 topics including entropy, Gibbs free energy, and thermodynamic favorability. The lesson begins with an overview and a solubility equilibria problem involving magnesium fluoride. It progresses to discussions on precipitation, KSP calculations, and the concepts of entropy and free energy. The lesson also explores thermodynamic favorability, the relationship between free energy and equilibrium, and concludes with AP practice problems. Students are encouraged to understand these concepts for future chemistry courses, despite some not being on the 2020 AP exam.

What units are not covered in the 2020 AP Chemistry exam but are still recommended for study?

• Units 9 and 10

• Units 10 and 11

• Units 8 and 9

• Units 1 to 7

What is entropy often misconceived as?

• Molecular speed

• Disorder

• Heat

• Energy

Which phase change is associated with an increase in entropy?

• Gas to liquid

• Solid to gas

• Liquid to solid

• Solid to liquid

What does a negative Delta G indicate about a process?

• It is thermodynamically favored

• It is not thermodynamically favored

• It requires external energy to occur

• It is at equilibrium

What condition often results in Delta G being zero?

• The reaction is at equilibrium

• The reaction is extremely fast

• The reaction cannot occur

• The reaction is endothermic

What accelerates the reaction when hydrogen peroxide is applied to a cut?

• Potassium iodide

• Calcium carbonate

• Catalase enzymes in the skin

• Manganese dioxide

What indicates that the decomposition of calcium carbonate is an endothermic process?

• Delta H is negative

• Delta H is positive

• Delta G is negative

• Delta S is negative

Which scenario is considered the best-case scenario for a reaction to be favored at all temperatures?

• Delta H is positive and Delta S is negative

• Both Delta H and Delta S are negative

• Both Delta H and Delta S are positive

• Delta H is negative and Delta S is positive

What drives the dissolution of ammonium nitrate in water?

• Both enthalpy and entropy

• Entropy only

• Enthalpy only

• Neither enthalpy nor entropy

Why is the dissolution of urea considered endothermic?

• Because it releases heat to the surroundings

• Because it absorbs heat from the surroundings

• Because it decreases the entropy of the system

• Because it does not change the temperature of the surroundings