Mixtures

What are the two types of mixtures?

Heterogeneous

What is the difference?

Heterogeneous mixtures have particles spread out unevenly throughout it.

Homogeneous

Homogeneous mixtures have particles spread out evenly throughout it

Are solutions homogeneous or heterogeneous?

Dissolved particles will not come out of solution, no matter how long the solution stands (assuming that the solution is covered)

The solution is clear and transparent

The solution will pass through the finest filters

The solution is in a single phase, usually liquid

Basic Properties of a Solution

Solute Any solution made with an alcohol

Solvent Solution in which water is the solvent

Aqueous Substance that gets dissolved

Tincture Substance that does the dissolving

Types of Solutions

Gas Solutions: A solution consisting of gases or vapors dissolved in one another

Liquid Solutions: A solution consisting of a liquid solvent, in which a gas, liquid or solid is dissolved

Solid Solution: A solution consisting of solids uniformly spread throughout one another at the atomic/molecular level.

Boiling Point Elevation/Freezing Point Depression

If you dissolve a solute in water, it will raise the boiling point, and lower the freezing point. You can find out how much by using the following equation:

T = Kf/Kb x m x DF

T

T = Kf/Kb x m x DF

Change in Temperature

Kf/KbFreezing point Depression Constant (1.87 degrees Celsius/molal)

or

Boiling point Elevation Constant (.52 degrees Celsius/molal

m Molal (moles solute/kg solvent)

DF Dissociation factor (how many parts solute breaks up into)

Now, it’s your turn!

Use the equation to find the freezing point depression.

T = Kf/Kb x m x DF

Kf = 1.87 *C/m Kb = .52 *C/m

2 moles of NaCl are dissolved in 500 grams of water. Calculate the freezing point depression.

T = 1.87 *C/m x 4m x 2 = 14.96

New freezing point is -14.96 *C

Solubility

The solubility of something shows the maximum amount of solute that can

dissolve in a certain amount of solvent.

What are the 3 main factors that have an effect on solubility?

Pressure

Nature of solute/solventTemperature

The four factors affecting the rate of solution are:

StirringAmount of Solute already dissolved

Temperature

SIZE OF THE PARTICLES.

(NO PICTURE AVAILABLE)

At 30 *C, how many grams of HCl will be needed to saturate 50 grams of water?

About 33 grams

At 70 degrees, you have dissolved 60 grams of NH4Cl in 100 grams of water. Is the solution unsaturated, saturated or supersaturated?

SATURATED!

By using the solubility properties of gases and solids, is NH3 a gas or solid?

GAS

How do we know?

Since the solubility goes down as temperature goes up, it has to be a gas!

• A dilute solution is one in which the amount of solute dissolved is small in relation to the amount of solvent.

• A concentrated solution is one in which a relatively large amount of solute is dissolved.

YEP.

So, can a dilute solution be a saturated solution also??

You now know everything there is to know about solutions.

But congratulations anyways…

Well, not everything.