A homogeneous mixture containing a solute dissolved in a solvent. Solutions A homogeneous mixture containing a solute dissolved in a solvent.

Homogeneous mixtures Any two samples have the same composition particles are SO SMALL atoms, molecules, ions THEY CAN’T BE SEEN & will pass through a filter So how do you separate the components?

Two or more substances with different boiling points can be separated using fractional distillation (ex. Crude oil)

How do substances dissolve in each other?

When a non-polar, organic molecule dissolves it breaks apart into individual molecules. Called solvation, & forms a non-electrolytic solution.

Click the pic.

NaCl separates into ions (called ionization) NaCl separates into ions (called ionization). When the water molecules surround the ions its called hydration & it forms an electrolytic solution.

How will these salts dissociate/ionize? NaCl(s)  Na+(aq) + Cl-(aq) Na2SO4 (s)  2Na+(aq) + SO42-(aq) Pb(NO3)2 (s) Pb2+(aq) + 2NO3-(aq)

Why are some ionization reactions endothermic and some exothermic????

Separate the solute into ions, atoms or molecules. +∆H Forming a solution Occurs in 3 steps “Expand” the solvent Overcome the IMF to make room for the solute. +∆H “Expand” the solute Separate the solute into ions, atoms or molecules. +∆H Allow solvent and solute to COMBINE and form sol’n. -∆H ∆Hsol’n = ∆H1 + ∆H2 + ∆H3

Example: NaCl(s)  Na+(aq) + Cl-(aq) ∆H1 = +21kJ/mol REQUIRED to overcome Hydrogen bonding in H2O (IMF) ∆H2 = +786kJ/mol REQUIRED to separate the salt into ions ∆H3 = -783 kJ/mol IS RELEASED when ions and polar water molecules attract ∆Hsol’n = +24kJ/mol This is an endothermic change….. Generally unfavorable in the universe. So….why does NaCl dissolve so readily?

Entropy

Types of Solutions Solid solutions a.k.a alloy Gas solutions 2 or more gases or vapors dissolved ex. AIR Solid solutions a.k.a alloy copper + zinc = brass copper + tin = bronze Amalgam An alloy made with mercury

Liquid solutions liquid, solid or gas dissolved in liquid 2 liquids that mix = miscible 2 liquids that don’t mix = immiscible (aq) water is the solvent tincture alcohol is the solvent

water is the universal solvent because it dissolves almost everything

Solubility Rules Like dissolves like polar dissolves polar non-polar dissolves non-polar Similar IMF will dissolve in each other

Oil and Water

The End