Notes on Chemical Equilibrium

Introduction to Balance

• Life involves various forms of balance: finance, diet, work-life, etc.
• In science, the term for balance is equilibrium.
• Disruptions to balance can have wide-ranging effects.

Equilibrium in Nature

• Natural systems strive for equilibrium.
• Examples: Deer population regulation through resource limits and predator dynamics.
• Personal choices (like diet) can still allow for temporary imbalances.

Chemical Reactions and Equilibrium

• Common perception: chemical reactions have a clear start and end.
• Reality: many reactions do not result in pure products.
• Forward Reaction: Reactants form products.
• Reverse Reaction: Products can revert back to reactants.

Chemical Equilibrium

• Occurs when forward and reverse reactions happen at the same rate.
• Equilibrium is represented by a double arrow (⇌) in chemical equations.
• Key Point: Reactions do not stop at equilibrium; they continue to occur in both directions.

Disturbances to Equilibrium

• Changes in concentration, temperature, or pressure can disturb equilibrium.
• Le Chatelier's Principle: A system at equilibrium will shift in a direction that minimizes stress when disturbed.

Concentration Changes

• Increasing a reactant shifts equilibrium to produce more products.
• Removing product shifts equilibrium to replace it.
• Example: Haber process for ammonia production.

Pressure Changes

• Reactions involving gases are affected by pressure.
• Increasing pressure favors the direction that produces fewer moles of gas.
• Haber process operates at high pressures (around 200 atm).

Temperature Changes

• Endothermic Reactions: Favorable at higher temperatures (heat added).
• Exothermic Reactions: Favorable at lower temperatures (heat removed).

The Haber Process

• Example of industrial application of equilibrium principles.
• Haber discovered continuous removal of ammonia allows reaction to favor products.
• Acknowledgments to Le Chatelier for foundational principles, despite his unsuccessful attempts.

Conclusion and Summary

• Key takeaways:
  • Equilibrium is about balance, not stasis.
  • Chemical equilibrium is affected by concentration, temperature, and pressure.
  • Le Chatelier's Principle helps predict how systems respond to changes.
• Fun demonstration of cobalt ions showing color change with equilibrium shifts.
• Reminder to maintain balance in personal lives as well.

Credits

• Written by Edie Gonzales, edited by Blake DePastino.
• Chemistry consultant: Dr. Heiko Langner.
• Filmed, edited, and directed by Nicholas Jenkins.
• Graphics by Thought Cafe.