Differences in Solubility Conditions of Solubility Miscible vs. Immiscible Colligative Properties

Why are there differences in solubility? General Rule = Like Dissolves Like What makes substances similar or alike? CASE #1: Types of bonds CASE #2: Polarity CASE #3: Type of intermolecular force

CASE #1 : TYPES OF BONDING EX. Salt (NaCl) + water (H2O) Ionic compounds dissolve in aqueous solutions via a process called hydration.

CASE #2: POLARITY EX. Water + Animal Fat Salt (NaCl) + Vegetable Oil LiCl + C6H5CH3 (Toluene)

CASE #3: TYPE OF IMF MISCIBLE = dissolve in each other at all proportions, have similar IMFs solvent considered to be substance present in larger amount EX. alcohol + water IMMISCIBLE = substances do NOT dissolve in each other at all proportions, do not have similar IMFs EX. water + oil Italian Salad Dressing

What are colligative properties? Properties that depend on number of solute particles in a solution or concentration

VAPOR PRESSURE DECREASES If you increase the concentration, the vapor pressure is the pressure above the liquid in a closed container As # of solute particles increases, they attract molecules of solvent and hold solvent particles in solution (Prevent Escape!)

BOILING POINT INCREASES Boiling Point is the Temperature where atm pressure = vapor pressure. As # of solute particles increase, vapor pressure decreases thus it will take more energy to raise the vapor pressure back to equilibrium with atm pressure.

FREEZING POINT DECREASES Adding solute to solvent lowers the normal freezing point. Solute interferes with formation of solid crystals. In order to freeze molecules must be attracted to each other (clump/cluster together) and if solute molecules are in the path, solvent particles can’t clump.

Why do we apply salt to roadways/walkways in the winter? LOWERS FREEZING POINT! We use salt solutions involving NaCl and CaCl.

Why do we apply salt to roadways/walkways in the winter? LOWERS FREEZING POINT!