7.mm

Impact of Small Changes in ΔG on K

Central Concept: A Small Change in ΔG Makes a Big Difference in K

• Relationship Between ΔG and K

  • ΔG=−RTln⁡K Logarithmic relationship means small energy differences have a large effect on K.

• Energy Differences and KKK:

  • Even a tiny energy difference, such as 1.7 kJ mol−11.7 results in an appreciable shift in equilibrium.

  • Example: Hydration of aldehydes where 1.7 kJ mol−11.7 changes the balance between aldehyde and hydrate.

• Range of Energy Differences:

  • For energy differences between 0 and 50 kJ mol−1:

    • K changes drastically, illustrating the sensitivity of equilibrium to energy.

• Energy Units:

  • Conversion: 1 kcal=4.184 kJ

  • Nutrition connection: Human daily energy output is around 10,000 kJ

• Impact on Product Yield:

  • A difference of 10 kJ mol−110:

    • Equilibrium constant KKK becomes > 50.

    • Results in ~98% product formation.

• Conclusion:

  • Small energy differences drive large equilibrium shifts, making reactions highly efficient at producing desired products with relatively minor energetic advantages.