A. Homogeneous Mixture- uniform A. Homogeneous Mixture- uniform throughoutthroughout

B. One or more substances B. One or more substances dissolved in anotherdissolved in another

C. Grouped by stateC. Grouped by state Solid - metal alloysSolid - metal alloys Liquid – chemicals we use in Liquid – chemicals we use in

experimentsexperiments Gas - airGas - air

Solvent – the liquid Solvent – the liquid in which something in which something will be dissolvedwill be dissolved

Solute – the Solute – the substance (usually a substance (usually a solid) being solid) being dissolveddissolved

What makes something What makes something dissolve?dissolve?

Solubility – the Solubility – the amount of a amount of a substance that substance that dissolves in a given dissolves in a given quantity of solvent at quantity of solvent at a certain a certain temperature.temperature.

Determined byDetermined by TemperatureTemperature PressurePressure Nature of solute and Nature of solute and

solvent (Like dissolves solvent (Like dissolves like or polar dissolves like or polar dissolves polar.)polar.)

(click on curve for dissolving (click on curve for dissolving animations)animations)

How can you increase the How can you increase the rate of solubility?rate of solubility?

1. Agitation- stir it1. Agitation- stir it 2. Temperature – Increase in 2. Temperature – Increase in

temp usually causes an temp usually causes an increase in solubility due to increase in solubility due to an increase in KE, this causes an increase in KE, this causes more collisions between more collisions between liquid molecules and crystals.liquid molecules and crystals.

3. Surface area – Increase in 3. Surface area – Increase in surface area will increase surface area will increase solubility – also due to more solubility – also due to more direct collisions between direct collisions between liquid and crystals.liquid and crystals.

Can an infinite amount of Can an infinite amount of solute be dissolved in a solute be dissolved in a

given amount of solvent?given amount of solvent?

No!No! 1. 1. Saturated solutionSaturated solution – contains maximum – contains maximum

amount of solute for a given amount of amount of solute for a given amount of solvent at a certain temp.solvent at a certain temp.

2. 2. Unsaturated solutionUnsaturated solution – contains less – contains less solute than a saturated solution.solute than a saturated solution.

3. 3. Supersaturated solutionSupersaturated solution – contains more – contains more solute than theoretically possiblesolute than theoretically possible

What if there is more What if there is more solute than can be solute than can be

dissolved into a solution?dissolved into a solution?

EquilibriumEquilibrium is reached – same is reached – same number of solute particles are number of solute particles are solvating (dissolving) as desolvating solvating (dissolving) as desolvating (undissolving).(undissolving).

What about liquids?What about liquids?

1. Two liquids that dissolve in each other 1. Two liquids that dissolve in each other are called are called misciblemiscible..

2. Two liquids that don’t dissolve in each 2. Two liquids that don’t dissolve in each other are other are immiscibleimmiscible. Example: oil & . Example: oil & waterwater

Do gases dissolve the Do gases dissolve the same way as solids?same way as solids?

1. Solubilities of gases are 1. Solubilities of gases are greatergreater in cold water than in hot water. This in cold water than in hot water. This is because bubbles form in is because bubbles form in warmwarm water allowing dissolved gases to water allowing dissolved gases to escape.escape.

2. Solubility of a gas in a liquid is 2. Solubility of a gas in a liquid is directly proportionaldirectly proportional to the pressure to the pressure of the gas above the liquid – of the gas above the liquid – Henry’s Henry’s LawLaw..

Henry’s Law & Soda PopHenry’s Law & Soda Pop

If pressure is ↑↑↑ If pressure is ↑↑↑ then COthen CO22 stays in stays in the liquid (high the liquid (high solubility).solubility).

If pressure is ↓↓↓ If pressure is ↓↓↓ then CO then CO22 escapes escapes the liquid (low the liquid (low solubility).solubility).

When does a When does a supersaturated solution supersaturated solution

exist?exist? 1. When the temp is 1. When the temp is raisedraised in a saturated in a saturated

solution and excess solid is dissolved. If solution and excess solid is dissolved. If the system is cooled slowly then that the system is cooled slowly then that excess may not crystallize but stay in the excess may not crystallize but stay in the solution. So we call it solution. So we call it supersaturatedsupersaturated..

2. You can desupersaturate a solution by 2. You can desupersaturate a solution by placing a crystal in it – this causes excess placing a crystal in it – this causes excess solute to crystallize. Now the system will solute to crystallize. Now the system will reach a reach a dynamic equilibriumdynamic equilibrium..

Is there an energy Is there an energy change when something change when something

is dissolved?is dissolved? Dissolving a solid in a liquid is Dissolving a solid in a liquid is

usuallyusually endothermicendothermic. .

Which means it will feel cool to the Which means it will feel cool to the touch.touch.

Why is water so good at Why is water so good at dissolving things?dissolving things?

Because water is polar it’s positive end is Because water is polar it’s positive end is attracted to the negative end of polar attracted to the negative end of polar covalent or ionic compounds. The covalent or ionic compounds. The negative end is attracted to positive ends.negative end is attracted to positive ends.

Try theseTry these

Solve for x:Solve for x:

1.1.3838 = = xx 9595 = = 3535

100100 40 40 100 x100 x

2. If a recipe calls for 4 eggs and .5 cups 2. If a recipe calls for 4 eggs and .5 cups of oil but you only have 3 eggs, how of oil but you only have 3 eggs, how much oil will you need? (Set up a much oil will you need? (Set up a proportion.)proportion.)

Solubility CurvesSolubility Curves

We can use the solubility We can use the solubility curve to figure out a curve to figure out a

substance’s solubility at substance’s solubility at different temperatures.different temperatures.

How many grams of KClOHow many grams of KClO33 will will dissolve in 100g of water at 80dissolve in 100g of water at 80ooC?C?

How many grams of NaNOHow many grams of NaNO33 will will dissolve in 400g of water at 50dissolve in 400g of water at 50ooC?C?