Chemistry Unit 10- Mixtures and Solutions

Solute

Dissolved substance

Solvent

Dissolving substance, like H2O

H2O is polar, polar solutes dissolve better with polar solvents

Nonpolar substances dissolve in nonpolar solvents

Soluble

Solid solute that dissolves

Insoluble

Solid solute that doesn't dissolve

Miscible

2 liquids mixed

Immiscible

2 liquids don't mix

Like Dissolves Like

- Solutes and most ionic compounds because it's polar

- Nonpolar liquids mix with each other nonpolar liquids

- Other solvents needed for oils

- Polar and nonpolar do not mix

-Water- Strong IMFs

- Oil- No IMFs

Alcohol dissolves both polar and nonpolar liquids

Suspension/Heterogenous Mixtures

A heterogenous mixture in which particles can be seen and easily separated by settling or filtration

Colloids

Made of 2 or more phases

Medium size particles, don't settle out (1-1000nm)

ex: Jelly, jello, mayo, paint, milk, blood, smoke, fog, foam, whipped cream, pollen in air

Sits in air/liquid, moving. Heterogenous mixtures settle at bottom/on top of something

Homogenous Mixtures/Solutions

Particles conform to one phase, but it can be any phase

ex: Air (gas solution, mix of O2, CO2, N2)

Dalton's law of partial pressure

ex: Alloys: Solid solution of metals: Brass, stainless, sterling silver

Tincture

Solution that is alcohol based. Alcohol is solvent, not H2O

Emulsion

Mixture of oil and water that stays mixed because of an emulsifier

Mayo (eggs are the emulsifier), Lotions

Electrolytes

Ionic solutions that contain cations and anions that disassociate in water and conduct electricity

NaCl -> (Na+) + (Cl-)

C12H22O11 -> C12 H22 O11 non electrolyte, covalent

Solubility

How much solutes dissolve in 100mL of H2O at various temperatures

Categories of Solubility

Unsaturated

Saturated

Supersaturated

1. Unsaturated Solution

Less dissolved solute for a given temperature than a solvent could hold

More solute can be added to dissolve

ex: Cup of hot water with a small amount of NaCl dissolved in it, where more salt could be added and it would still dissolve

2. Saturated Solution

Completely full, maximum substance amount

Maximum amt. of solute in a given amount of solvent at a specific temperature

On solubility graph line

No more solute would dissolve

ex: Cup of hot water with NaCl, add more NaCl it becomes supersaturated.

3. Supersaturated Solution

Solution that contains more dissolved solute than the max (sat. solu) at the same temp due to cooling and drop in solubility

Very unstable

ex: Honey- Leave it for a bit but recrystallizes, rock candy, crystal formations

Points above saturated line formation

Colligative Properties of Solutions

Properties that make solutions different from pure water

Depends on the # of particles (concentration), not the indentity of the solute

Freezing Point Depression, boiling point elevation

Colligative Property 1. Freezing Point Depression

Solutions have a lower freezing point of water

Solute particles BLOCK the IMFs from forming a solid, so KE must be lower

Putting salt on roads in winter allows the road to stay wet a lower temperature and avoid turning into ice

Colligative Property 2. Boiling Point Elevation

Boiling point occurs when VP = ATM pressure

Decrease VP, increase BP

Increase VP, decrease BP

Adding solutes to H2O lowers VP (less evaporation, increase BP)

Takes more energy to increase evaporation (higher BP), increases VP to reach atm pressure

Solutions boil at a higher temp and freeze at a lower temperature than water

Wider range of temp in the liquid phase

Molarity

Most common unit of solution concentration

Molarity = (mols of solid)/(liters of solution)

Dilutions

Making a solution of lower concentration from a stock solution

(M1)(V1) = (M2)(V2)

M: Molarity

V: Volume