II. Solutions and their properties

A. Remember this from the 1st semester?!

• 1. Mixtures- physical blends of 2 or more kinds of matter each of which retains its own properties, 95% of all things in the universe are mixtures

• a. homogeneous mixture - uniform in composition

• 1) ex: salt water, inks• 2). SOLUTIONS are a uniform mix

of two or more substances which are NOT chemically bonded and each component retains it original identity and properties -

----usually in liquid form!

• b. heterogeneous not uniform throughout,

• 1) ex: chocolate chip cookie, trail mix

• B. Parts of a solution– 1. A solution is a mixture of different

substances that are evenly distributed throughout. It can be between any two phases of matter.

• 2. Contains two parts: Solute and Solvent a. Solute- is the thing being dissolved: solid into liquid, or the

substance depending on the mixture.

• b. Solvent – the dissolving medium: The liquid, or larger amount of liquid or solid

depending on the mixture.

solute

solvent

smaller amount

• Which is the solute in a mixture of 10 mL HCl and 90 mLWater?

• The solute is the lesser amount so it’s the HCl!

C. Solutions are mixtures and depend on particle size.

• 1. Solutions- homogeneous mixtures where the particles are so small that they are not visible.

• They can be separated by boiling but not by filters.

• a.Ex. Salt water, Gatorade, Vinegar.

• 2. Colloids - homogeneous mixtures with intermediate sized particles – barely visible but definitely there- These particles are suspended, spread & reflect light (Tyndall effect), and can be separated by good filters.

• a. Ex: Hair gel, Jello, and Foggy nights

• These are NOT solutions!!!

• 3. Suspensions- heterogeneous mixtures with larger particles easily separated and will settle out of solution if the suspension sits long enough.

• a. Ex: Muddy water, sand, blood.

• These are NOT solutions!!

. Water and Electrolytes

• 1. Water is called the universal solvent because of the large number of materials that dissolve in it.

• The basis for this behavior is water’s polarity--- one end is slightly more negative & the other end is slightly more positive

• 2. Ionic solutes dissolve easiest in water- break apart into ions.

• a. Electrolytes are ionic compounds that break apart into ions and conduct electricity.

1) Ex: salt, HCl • b. Non-electrolytes dissolve as

molecules and do not conduct electricity.

1)Ex: Sugar, honey

Like dissolves Like

• 3. Nonpolar or Covalent compounds typically do not dissolve in water. – Oils, paints, or grease don’t easily

dissolve in water because they are so different from water

Solvation

NONPOLAR

NONPOLAR

POLAR

POLAR

Solvation

• Soap/DetergentSoap/Detergent– polar “head” with long nonpolar “tail”– dissolves nonpolar grease in polar water