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Ch.7 Energy, Rate and EquilibriumWorksheetSee all chapters
All Chapters
Ch.1 Matter and Measurements
Ch.2 Atoms and the Periodic Table
Ch.3 Ionic Compounds
Ch.4 Molecular Compounds
Ch.5 Classification & Balancing of Chemical Reactions
Ch.6 Chemical Reactions & Quantities
Ch.7 Energy, Rate and Equilibrium
Ch.8 Gases, Liquids and Solids
Ch.9 Solutions
Ch.10 Acids and Bases
Ch.11 Nuclear Chemistry
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Nature of Energy
First Law of Thermodynamics
Endothermic & Exothermic Reactions
Bond Energy
Thermochemical Equations
Heat Capacity
Thermal Equilibrium (Simplified)
Hess's Law
Rate of Reaction
Energy Diagrams
Chemical Equilibrium
The Equilibrium Constant
Le Chatelier's Principle
Solubility Product Constant (Ksp)
Spontaneous Reaction
Entropy (Simplified)
Gibbs Free Energy (Simplified)

Gibbs Free Energy represents energy associated with a chemical reaction that can be used to do work.

Gibbs Free Energy

Concept #1: Gibbs Free Energy (∆G)

Example #1: If ∆G is small and positive, which of the following statements is true?

Concept #2: Predicting Spontaneity

Example #2: PCl3 (g) + Cl2 (g) ⇌ PCl5 (g) At 25°C, ΔH° = - 92.50 kJ. Which of the following statements is(are) true?

Practice: What are the signs of ∆H, ∆S and ∆G for the spontaneous conversion of a solid into gas?

Practice: You calculate the value of ΔG for a chemical reaction and get a positive value. Which would be the most accurate way to interpret this result?

Practice: Consider the combustion of butane gas and predict the signs of ΔS, ΔH and ∆G.

C4H10(g) + 13/2 O2(g) ⟶ 4 CO2(g) + 5 H2O(g)      

Concept #3: Calculations of Gibbs Free Energy

Example #3: For a particular reaction, ΔH = - 111.4 kJ and ΔS = - 25.0 J/K. 

Calculate ΔG for this reaction at 298º K. What can be said about the spontaneity of the reaction at 298º K? 

Practice: A particular reaction has ΔG = –350 kJ and ΔS = –350 J/K at 24°C. How much heat will be released/absorbed?

Practice: For a reaction in which ΔH = 125 kJ and ΔS = 325 J/K, determine the temperature in Celsius above which the reaction is spontaneous.