Solubility Rules Solubility Rules & Reference Tables& Reference Tables

Components of a SolutionComponents of a Solution

SoluteSolute: substance : substance being dissolvedbeing dissolved

Ex: Salt, SugarEx: Salt, Sugar

Solvent:Solvent: substance substance doing the dissolvingdoing the dissolving

Ex: Water, HexaneEx: Water, Hexane

What Dissolves in What?What Dissolves in What?

Solute must Solute must form attractionsform attractions to the solvent. to the solvent.

Polars dissolve polarsPolars dissolve polarsNonpolars dissolve nonpolarsNonpolars dissolve nonpolars

Polar solvents dissolve Polar solvents dissolve mostmost ionic crystals ionic crystals

SolubilitySolubility:: How muchHow much solute can solute can

be dissolved in abe dissolved in a

volume of solvent undervolume of solvent under

certain conditions ofcertain conditions of

temp. and pressure.temp. and pressure.

Using Reference Table GUsing Reference Table G

Shows solubility in Shows solubility in grams of solute per grams of solute per 100 grams of water at 100 grams of water at different temperaturesdifferent temperatures

Saturated Solutions:Saturated Solutions: hold max solute hold max solute

possible at that temp.possible at that temp.

Table G: Table G:

Solubility curves Solubility curves show saturation levelsshow saturation levels at at

different temps (in 100g of water).different temps (in 100g of water).

Saturated Solutions are at Saturated Solutions are at EQUILIBRIUMEQUILIBRIUM..

Rate of dissolving = Rate of crystallizationRate of dissolving = Rate of crystallization

Ex: How many grams of NaNOEx: How many grams of NaNO33 are are

needed to create a sat. solution in 100g of needed to create a sat. solution in 100g of water at 50 water at 50 °°C?C?

Go to 50 Go to 50 °°C and up to NaNOC and up to NaNO33 and over. and over.

Answer: 116 gramsAnswer: 116 grams

Look at The Water!!Look at The Water!!

Table G is for 100 grams of water.Table G is for 100 grams of water.

Amount of water in your problem may be Amount of water in your problem may be different and you need to adjust you different and you need to adjust you answer.answer.

How many grams of NaNOHow many grams of NaNO33 are needed to are needed to

create a sat. solution in create a sat. solution in 300g of water300g of water at 50 at 50 °°C?C?

Answer: Answer: 116 grams x 3116 grams x 3 (three times as much (three times as much water!)water!)

Or you can use a proportion:Or you can use a proportion:

116 grams116 grams == x gramsx grams

100 g H100 g H2200 300g H300g H2200

Unsaturated Solutions:Unsaturated Solutions: could still hold could still hold

more solute at that temp.more solute at that temp.

Would fall “below the line” on Table GWould fall “below the line” on Table G

Ex: 40 g of NaNOEx: 40 g of NaNO33 in 100g water at 50 in 100g water at 50°°

Supersaturated Solutions:Supersaturated Solutions: hold more hold more

solute than they should at that temp.solute than they should at that temp.

Would fall “above the line” on Table GWould fall “above the line” on Table G

Ex: 140 g of NaNOEx: 140 g of NaNO33 in 100g water at 50 in 100g water at 50°°

How do Supersaturated Solutions How do Supersaturated Solutions Form?Form?

Created a saturated solution at a high Created a saturated solution at a high temp. and slowly let solution cool. temp. and slowly let solution cool.

Certain solutes can stay in solution (like Certain solutes can stay in solution (like sodium acetate).sodium acetate).

SupersaturatedSupersaturated

solutions are solutions are unstableunstable. .

Add just one moreAdd just one more

““seed crystal” to theseed crystal” to the

solution, all the excesssolution, all the excess

solute will precipitatesolute will precipitate

out quickly.out quickly.Supersaturated Sodium Acetate solution after seed crystal added

Describe These SolutionsDescribe These Solutions

Saturated, Unsaturated or Supersaturated?Saturated, Unsaturated or Supersaturated?

100 g NH100 g NH44Cl at 70Cl at 70°° in 100 g water in 100 g water

10 g SO10 g SO22 at 10 at 10°° in 100 g water in 100 g water

40 g NaCl at 9040 g NaCl at 90°° in 100 g water in 100 g water

100 g NH100 g NH44Cl at 70Cl at 70°° in in

100 g water100 g water

Falls above the line Falls above the line (Supersaturated)(Supersaturated)

10g SO10g SO22 at 10 at 10°° in 100g in 100g

waterwater

Falls below the line Falls below the line (Unsaturated)(Unsaturated)

40g NaCl at 9040g NaCl at 90°° in 100g in 100g

waterwater

Falls on the line Falls on the line (Saturated)(Saturated)

Concentrated Solutions:Concentrated Solutions:have a lot of solutehave a lot of solutedissolved in the solventdissolved in the solvent

Ex: Saturated solution of KIEx: Saturated solution of KIat 10at 10°°

135 grams in 100 g water 135 grams in 100 g water = pretty concentrated= pretty concentrated

Dilute Solutions:Dilute Solutions: only only

have a little solutehave a little solute

dissolved.dissolved.

Ex: Sat. solution of SOEx: Sat. solution of SO22

at 50at 50°°

4 grams in 100 g water 4 grams in 100 g water = relatively dilute= relatively dilute

Factors Affecting Factors Affecting SolubilitySolubility

Surface AreaSurface Area

More contact betweenMore contact between

solute/solvent particlessolute/solvent particles

the faster it dissolvesthe faster it dissolves

Crush substance into fineCrush substance into fine

powder to dissolve faster.powder to dissolve faster.

Use mortar and pestleUse mortar and pestle

Stirring or Agitation:Stirring or Agitation:

Allows for more solute/solventAllows for more solute/solvent

contact, and faster dissolving ofcontact, and faster dissolving of

solids and liquidssolids and liquids

However, stirring will disturbHowever, stirring will disturb

dissolved dissolved gasesgases and cause and cause

them to them to come out of solution.come out of solution.

Temperature of SolventTemperature of Solvent

Higher temperature solvents willHigher temperature solvents will

dissolve dissolve solid solutessolid solutes faster faster

Why?Why?

Solvent particles move fasterSolvent particles move faster

making contact faster with solute.making contact faster with solute.

GasesGases dissolve better when dissolve better when

the temperature of thethe temperature of the

solvent is solvent is colder.colder.

Ex: Ex: COCO22 gas in hot soda gas in hot soda

(flat) (flat) vs. cold soda (fizzy)vs. cold soda (fizzy)

Fish in aquariums needFish in aquariums need

the dissolved oxygen inthe dissolved oxygen in

the water, if the tempthe water, if the temp

gets too high theygets too high they

suffocatesuffocate

PressurePressureEffects gas solubilityEffects gas solubilityonlyonly

Why?Why?Increasing pressure onIncreasing pressure ona gas above a liquida gas above a liquidcauses more gascauses more gasmolecules to bemolecules to be““pushed” into solution.pushed” into solution.

Amount of Solute already DissolvedAmount of Solute already Dissolved

The more particles already in solution theThe more particles already in solution the

less solvent molecules available to dissolveless solvent molecules available to dissolve

new solute.new solute.

Miscible:Miscible:

liquids that dissolve in liquids that dissolve in any proportions (ex: any proportions (ex: alcohol and water)alcohol and water)

Immiscible:Immiscible:

liquids that liquids that do notdo not dissolve in any proportion dissolve in any proportion (ex: oil and water)(ex: oil and water)

Electrolytes:Electrolytes: Conduct electricity when dissolved in waterConduct electricity when dissolved in water

Why do they Conduct?Why do they Conduct?

Create Create mobile ions in solutionmobile ions in solution..The more concentrated the solution the The more concentrated the solution the

more it conductsmore it conducts

Includes:Includes:Soluble Ionic Compounds (ex: NaCl)Soluble Ionic Compounds (ex: NaCl)Acids (ex: HCl)Acids (ex: HCl)Bases (ex: NaOH)Bases (ex: NaOH)

Who Will Conduct?Who Will Conduct?

Which of the following compounds will conduct Which of the following compounds will conduct in solution?in solution?

CC66HH1212OO66

LiBrLiBr KOHKOH CHCH44

HH22SOSO44

NONO22

CC66HH1212OO66 Will NotWill Not (Covalent) (Covalent) LiBrLiBr Will (Ionic)Will (Ionic)KOHKOH Will (Base)Will (Base)CHCH44 Will NotWill Not (Covalent) (Covalent)

HH22SOSO44 Will (Acid)Will (Acid)

NONO22 Will NotWill Not (Covalent) (Covalent)

Reference Table FReference Table F

Describes which ionic compounds are Describes which ionic compounds are soluble or insoluble in water.soluble or insoluble in water.

Why are Some Insoluble?Why are Some Insoluble?

Certain combinations of ions hold together Certain combinations of ions hold together so strongly that water cannot dissolve so strongly that water cannot dissolve them into solutionthem into solution

PrecipitatesPrecipitates

PrecipitatesPrecipitates are are insolubleinsoluble ionic compounds formed in ionic compounds formed in double replacement reactions. double replacement reactions.

Determine which product is the Determine which product is the insoluble precipitate by using insoluble precipitate by using Table F.Table F.

You can separate a You can separate a precipitate by precipitate by filtrationfiltration..

The solid will stay on The solid will stay on the paper.the paper.

Is this soluble or not?Is this soluble or not? CaCOCaCO33

Carbonate (COCarbonate (CO33-2-2) is insoluble and Ca) is insoluble and Ca+2+2 as as

a partner is not an exceptiona partner is not an exception

Is this soluble or not?Is this soluble or not? NaNONaNO33

Nitrate (NONitrate (NO33-1-1) is always soluble, there are ) is always soluble, there are

not exceptionsnot exceptions

Is this soluble or not?Is this soluble or not? LiLi33POPO44

Phosphate (POPhosphate (PO44-3-3) is insoluble, however, ) is insoluble, however,

LiLi+1+1 is a Group 1 ion so it is is a Group 1 ion so it is an exceptionan exception and the compound is soluble.and the compound is soluble.

Soluble or Not?Soluble or Not?

Look out for exceptions!Look out for exceptions!CaSOCaSO44

MgSOMgSO44

PbCrOPbCrO44

LiLi22SS

NHNH44OHOH

InsolubleInsoluble CaSOCaSO44

SolubleSoluble MgSOMgSO44

InsolubleInsoluble PbCrOPbCrO44

SolubleSoluble LiLi22SS

SolubleSoluble NHNH44OHOH