Worksheet: Solvation

In this worksheet, we will practice describing the solvation mechanisms of molecules and ionic solids and the enthalpic and entropic changes involved.

Q1:

Why are N a + and C l ions strongly solvated in water but not in hexane?

  • AHexane molecules are much larger than water molecules, so they cannot pack around the small sodium and chloride ions as easily as water can.
  • BChloride ions deprotonate water molecules, and the resulting ion-ion interactions are stronger in total than the ionic bonds of sodium chloride. Hexane cannot be deprotonated and thus interacts with ions far more weakly.
  • CIon-dipole forces between the ions and water are stronger that the hexane-ion forces because hexane is nonpolar and thus interacts with ions far more weakly.
  • DDissolution of ions in hexane is entropically costly, as interactions with ions force the hexane molecules into less flexible folded conformations.
  • EWater molecules are bent, so ions can occupy the space between O H bonds. Hexane molecules are straight and thus cannot interact with ions in this way.

Q2:

Fill in the blanks: Typically, as the temperature of the solvent increases, solids become soluble, and gases become soluble.

  • Aless more
  • Bmore less
  • Cmore more
  • Dless less

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.