1) Solute the Stuff You Are Interested In

Solutions

1) Solute – the stuff you are interested in Solvent - that which dissolves the stuff Solution – the result

Solid/liquid – sugar water Liquid/liquid – alcohol in water Gas/liquid – carbon dioxide in water (soda pop)

Solid/solid – gold ring Liquid/solid – jello Gas/ solid – pumice stone (??)

Solid/gas – smoke Liquid gas – fog Gas/ gas – air

REMEMBER – A solution is a homogeneous mixture. You can vary its composition and you can mechanically separate the components.

2) Solutes can be Slightly Soluble Soluble Very soluble Insoluble – not soluble

Miscible - two liquids that dissolve in each other when they are mixed (acetic acid in water) Immiscible - two liquids that do not dissolve in each other when mixed (vinegar and oil salad dressing) Emulsion – two liquids that mixed together that are usually immiscible (mayonnaise)

Emulsifying agent – A substance the links the two immiscible components together forming an emulsion (egg whites used to link vinegar and oil together  mayonnaise) REMEMBER – Solubility deals with how much will dissolve.

Conditions that affect solubility include: a) Temperature goes up  Solubility of Gas goes down  Solubility of Solid generally increases  Solubility of Liquid has little effect

b) Pressure goes up  Solubility of Gas goes up (can of soda)  Solubility of Solid has no effect  Solubility of Liquid has no effect

c) Nature of solute and solvent- “Likes” dissolve “Likes” Ionic compounds are soluble in polar solvents -

(NaCl in H2O) Non-polar compounds are soluble in non-polar solvents- (Grease in gasoline)

3) Rate of solution – How fast a substance will dissolve

a) agitation – stirring dissolves sugar faster in water b) temperature - sugar dissolves faster in hot water c) particle size- big particles of sugar dissolve slower d) concentration - sugar dissolves slower in a solution that already contain sugar

4) Concentration - How much solute is dissolved in the solution a) Percent composition b) Molarity (2.5 M HCl = 2.5 moles HCl/1 Liter solution)

5) Strength – a measure of ability

a) Strong acids- HCl(aq) , HNO3(aq) , H2SO4(aq)

Weak acids – HC2H3O2(aq) , H2CO3(aq) , any other acid

b) Strong bases- NaOH(aq) , KOH(aq) (metal hydroxides from Group IA)

Weak bases – Al(OH)3(aq) , NH4OH(aq) , any other base

Concentrated Coffee not strong Coffee Dilute Tea not weak Tea 6) Solution types a) Unsaturated – solvent can still dissolve more solute b) Saturated – solvent can not dissolve any more solute c) Super saturated – Solvent has dissolved more solute than it normally holds at a given temperature (Honey)

7) Electrolytes – Aqueous solutions that conduct electricity Strong electrolytes – Strong acids & bases, soluble salts Weak electrolytes – Weak acids & bases Non-electrolytes – DI water & toluene (organic compounds)

8) Colligative properties are dependent on the number of particles present

Lowering of the vapor pressure Lowering of freezing point Increasing the boiling point Increasing the osmotic pressure

Osmosis- passage of solvent through a semi-permeable membrane Osmotic pressure-pressure required to halt the flow of solvent molecules through a semi-permeable membrane Reverse osmosis-solvent flows through the semi-permeable membrane in the reverse direction due to an increase in the osmotic pressure Living Cells

Isotonic solution- solution on the out-side of a cell has same osmotic pressure as the inside the cell. No effect

Hypotonic solution – If cell is surrounded by a solution of lower concentration of solute particles (lower osmotic pressure), water flows into the cell (plasmolysis)

Hypertonic solution – If cell is surrounded by a solution of higher concentration of solute particles (higher osmotic pressure), water flows out of the cell (crenation) Phase Diagram- H2O

Critical Temperature = 647.6 K Critical Pressure = 217.7 atm

Liquid

Vapor Solid Pressure Gas Triple Point 4.58 mm of mercury 0.0098 oC

Temperature

o Freezing point same as melting point = 0 C for H2O o Boiling point same as condensation point = 100 C for H2O

Boiling point is the temperature where the vapor pressure of a liquid is equal to the applied pressure.

Hfusion = amount of energy required to convert 1.0 gram of stuff from

a solid to a liquid. Hfusion H2O = 80 calories /gram.

Hvaporization = amount of energy required to convert 1.0 gram of stuff

from a liquid to a gas. Hvaporization H2O = 540 calories /gram.

Calorie = amount of energy required to raise the temperature of one

gram of H2O one degree Celsius.

BTU (British Thermal unit) = amount of energy required to raise the

temperature of one pound of H2O one degree Fahrenheit.

o Specific Heat (H2O/Solid) = Sp Ht (H2O/Gas) = 0.50 cal/( g x C) o Specific Heat (H2O/Liquid) = 1.0 cal/( g x C) 9) Hard water – specifically contains Ca+2, Mg+2 or Fe+3 ions - precipitates form between these ions and carbonates

-1 Temporary hard water - specifically contains bicarbonate ions (HCO3 ) - boiling will remove the hardness

Ca(HCO3)2(aq)  CaCO3(s) + (H2CO3 = H2O(l) + CO2(g) )

10) Soap – a link between polar water and non-polar oil drops

acid + base  salt + water

Lard + boiled wood ashes  soap + water

stearic acid + sodium hydroxide  sodium stearate + water

+1 -1 C17H35COOH(s) + NaOH(aq)  Na C17H35COO (aq) + H2O(l)

The Effect of Hard water on soap

+1 -1 2Na C17H35COO (aq) + CaCl2(aq)  Ca(C17H35COO) 2(s) + 2NaCl(l) Lost soap Bath tub Scum 11) Water of hydration

. CuSO4 5H2O copper(II) sulfate pentahydrate . CoCl2 6H2O cobalt(II) chloride hexahydrate

Hygroscopic – gains H2O from atmosphere

Deliquescent - gains H2O from atmosphere & turns to a liquid-like solution

Efflorescent – loses H2O to atmosphere

Dessicant (Drying Agent)- used to keep chemicals dry in a dessicator 12) Acid-Base reactions “ Neutralization reactions” “Double Replacement Reactions”

Acid + base  salt + water

HCl(aq) + NaOH(aq)  NaCl(aq) + HOH(aq)

NaCl is the Salt of the Base – NaOH NaCl is the Salt of the Acid – HCl

and Ba3(PO4)2 is the salt of the Base-Ba(OH)2 and the acid-H3PO4

Primary Standard- 1) Usually solid 2) High molecular mass 3) Stable at 100oC 4) High purity

Indicator- Phenolphthalein Acid/colorless Neutral/colorless Base/pink

Indicators tell when the titration is over

13) Buffers – resist changes in pH (see pH/pOH calculations)

a) Sodium bicarbonate neutralizes an acid

NaHCO3 + HCl  NaCl + H2CO3

( H2CO3  H2O + CO2)

b) Sodium bicarbonate neutralizes a base

NaHCO3 + NaOH  Na2CO3 + H2O

In both cases the sodium bicarbonate either removes H+1 or OH-1 from the solution. This is how a buffer works. Blood is a very complex buffer system with a pH of about 7.4 The primary buffer is a mix of -1 H2CO3 (H2O(l) and CO2(g) ) and HCO3 . Stoichiometry a) Mass-Mass Problems

1) Balance the reaction 2) Calculate the molecular mass of the known and the unknown 3) Calculate the number of moles of known 4) Calculate the number of moles of unknown 5) Calculate the number of grams of unknown

Grams known  moles known  moles unknown  grams unknown

MM of Known Balanced MM of unknown Reaction

Example

Calculate the mass of nitrogen needed to make 34 grams of ammonia.

1) Balance the reaction:

N2 + 3H2  2NH3

2) Calculate the molecular mass of the known and the unknown:

known [email protected] = 14.0 unknown 2N @ 14 = 28 g N2

3H @ 1.0 = 3.0 1 mole N2

17 g NH3

mole NH3 3) Calculate the number of moles of known:

(34 grams NH3)(1mole NH3/17 grams NH3) = 2 moles NH3

4) Calculate the number of moles of unknown:

(2 moles NH3) ( 1 mole N2 / 2 moles NH3) = 1 mole N2

5) Calculate the number of grams of unknown:

(1 mole N2)(28 grams N2/mole N2) = 28 grams N2

All Together

grams N2 = (34 grams NH3) (1mole NH3) ( 1 mole N2) (28 grams N2) = 28 grams N2

(17 grams NH3) (2 moles NH3) (1 mole N2)

b) Molarity = moles solute/ Liter solution

2.0 moles NaOH/ 1 Liter solution = 2.0 molar NaOH = 2.0 M NaOH

Calculate molarity (moles/Liter) Convert: Liters  moles  grams Grams  moles  Liters

c) Dilution

Conc1 x Vol1 = Conc2 X Vol2

d) Percent composition = (grams solute/grams solution) x 100

Convert grams solute  grams solution grams solute   grams solvent grams solvent   grams solution e) pH / pOH / [H+1] / [OH-1]

1) acid pH =-Log [H+1] [H+1] is the concentration of hydrogen ions in moles/Liter

2) base pOH =-Log [OH-1] [OH-1] is the concentration of hydroxide ions in moles/Liter

Calculator work Type 1: [H+1] / Log / (+/-) gives pH Type 2: (+/-) / Log / [H+1] / enter gives pH

[H+1] can be replaced with [OH-1] for bases

3) Acid [H+1] = 10-pH

4) Base [OH-1] = 10-pOH

Calculator work

Type 1: pH / (+/-) / inverse Log gives [H+1] Type 2: inverse Log / (+/-) / pH / enter gives [H+1]

pH can be replaced with pOH for bases

5) acid/base pH + pOH = 14 More Acidic Neutral More Basic pH 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

pOH 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Strong Acid Weak Acid Weak Base Strong Base HCl HC2H3O2 NH4OH NaOH Stomach Acid Vinegar Ammonia Water Oven Cleaner

De-ionized water