The Science in Ice Tea How sweet it is!

Definitions  Concentration – The measure of the amount of one substance dissolved (or suspended) in another.  Solution – The combination of solute and solvent  Solute – The stuff being dissolved (usually a solid)  Solvent – The stuff doing the dissolving (usually a liquid)

What’s the solute and solvent?  A spoonful of sugar in water?  A drop of food coloring in water?  Oregano in marinara sauce?  With two liquids, usually the one of larger quantity is the solvent.  However, no matter the quantity, water is always a solvent.

Water  Water is considered the universal solvent.  Not because it dissolves everything, but because it dissolves more solutes than any other solvent.

3 Kinds of Solutions  Unsaturated  Saturated  Supersaturated - Can still dissolve more solute - Can still dissolve more solute - Has the maximum amount of solute that the solvent can dissolve - Has the maximum amount of solute that the solvent can dissolve - Start getting undissolved solute as sludge. - Start getting undissolved solute as sludge.

Solubility  If the solute does dissolve in the solvent, it is said to be soluble in that solvent  If the solute doesn’t dissolve, (floats on top or sinks to bottom) it is said to be insoluble in that solvent.  Some solutes may be soluble in one solvent and insoluble in a different solvent

Liquid Pairs  When one liquid dissolves in another liquid, they are said to be a miscible pair.  If the two liquids don’t mix (one doesn’t dissolve in the other) they are said to be an immiscible pair.

What makes them miscible?  Whether or not the pair is miscible depends on their polarity. While both polar and non-polar molecules are overall neutral, a polar molecule has a negative half and a positive half  Two polar molecules are miscible.  Two non-polar molecules are miscible  A polar and a non-polar molecule together are immiscible.

Degrees of Separation  Dissolving – The molecules of a solid separate from each other in a solvent.  Ex. One salt crystal separates from the other crystals in a block. Or, a sugar molecule separates from other sugar molecules in a sugar cube.

Degrees continued  Dissociation – when parts of the molecule separate from each other, each carrying a charge.  Ex. In a salt crystal, the Na + separates from the Cl -  Sugar is a covalent compound and doesn’t dissociate

Colligitave Properties  Colligitave properties - properties that change as the concentration changes.  The 2 most common examples are: Boiling Point Elevation Freezing Point Depression