Chemistry Chapter 13 Test: Mixtures and Solutions

immiscible

describes two liquids that can be mixed together but separate shortly after you cease mixing them

as the solution's temperature increases, the solubility of a gaseous solute

decreases

heterogeneous mixture

one that does not have a uniform composition and in which the individual substances remain distinct

dilution

the process of reducing the concentration of a solute in solution, usually by mixing with more solvent

electrolyte

An ionic compound whose aqueous solution conducts an electric current

Brownian motion

the erratic, random, movements of colloid particles that results from particle collisions

saturated

contains the maximum amount of dissolved solute for a given amount of solvent

solvent

the substance that dissolves a solute to form a solution

Henry's law

states that at a given temp, the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid

concentration

a measure of how much solute is dissolved in a specific amount of solvent or solution

suspension

a type of heterogeneous mixture whose particles settle out over time and can be separated from the mixture by filtration

unsaturated

contains less dissolved solute than a saturated solution

homogeneous mixture

one that has a uniform composition throughout and is always a single phase

colloid

a heterogeneous mixture of intermediate-sized particles that do not settle out

soluble

describes a substance that can be dissolved in a given solvent

miscible

describes 2 liquids that are soluble in each other

supersaturated

contains more dissolved solute than a saturated solution at the same temperature

Tyndall effect

The scattering of light by colloidal particles

solute

one or more substances dissolved in a solution

insoluble

Describes a substance that cannot be dissolved in a given solvent

solvation

The process of surrounding solute particles with solvent particles to form a solution

molarity

the number of moles of solute per liter of solution

colligative property

a physical property of a solution that depends on the number, but not the identity, of the dissolved solute particles

solution

a uniform mixture that can contain solids, liquids, or gases; also called a homogeneous mixture

osmosis

the diffusion of solvent particles across a semipermeable membrane from an area of higher concentration to lower

HETEROGENEOUS MIXTURES

DO NOT BLEND SMOOTHLY TOGETHER

SUSPENSION

------>CONTAINS PARTICLES THAT SETTLE OUT IF LEFT UNDISTURBED

------->CAN SEPARATE THE PARTICLES THROUGH FILTRATION

EXAMPLES

• COOKING - FLOUR AND CORNSTARCH FOR THICKENING

• RIVER WATER

THIXOTROPIC MIXTURES

• HAVE SOLID AND LIQUID LIKE PROPERTIES

• TOOTHPASTE

• PAINT

COLLOIDS

• A HETEROGENEOUS MIXTURE OF INTERMEDIATE-SIZED PARTICLES

• 1NM - 1000 NM

• DO NOT SETTLE OUT

• CANNOT BE SEPARATED BY SETTLING OR FILTRATION

• EXAMPLES - P470

• BUTTER, MILK, WHIPPED CREAM, SMOKE

BROWNIAN MOTION

For colloids

• THE CHAOTIC MOVEMENT OFCOLLOIDAL PARTICLES

• CAUSED BY COLLISIONS OF THE MOLECULES

• HELPS PREVENT SETTLING

TYNDALL EFFECT

for colloids

• THE SCATTERING OF VISIBLE LIGHT BY COLLOIDAL PARTICLES

COAGULATION

for colloids

• THE ADDITION OF IONS HAVING A CHARGE OPPOSITE TO THAT OF THE COLLOIDAL PARTICLES

• PARTICLES CLUMP TOGETHER TO FORM HEAVIER AGGREGATES AND PRECIPITATE FROM THE DISPERSION

• CHEESE MAKING• CURDS (SOLID) AND WHEY (LIQUID)

HOMOGENEOUS MIXTURES

• HAS A UNIFORM COMPOSITION THROUGHOUT, A SINGLE PHASE

• SOLUTIONS

-----> • CAN EXIST AS A GAS, A LIQUID, OR A SOLID

-------------> • MAJORITY ARE LIQUIDS

• SOLUTE

------>• DISSOLVED PARTICLES IN A SOLUTION

• SOLVENT

------->• THE DISSOLVING MEDIUM IN A SOLUTION

soluble and insoluble

SOLUBLE

• A SUBSTANCE THAT DISSOLVES IN THAT SOLVENT

• INSOLUBLE•

A SUBSTANCE THAT DOESN'T DISSOLVE IN THAT SOLVENT

• "LIKE DISSOLVES LIKE"

• WHY OIL AND WATER DO NOT MIX!

miscible and immiscible

usually between 2 liquids

MISCIBLE

• TWO LIQUIDS THAT ARE SOLUBLE INEACH OTHER

• IMMISCIBLE

• TWO LIQUIDS THAT CAN BE MIXED TOGETHER BUT SEPARATE SHORTLY AFTER

----->• SALAD DRESSING

EXPRESSING CONCENTRATION

• CONCENTRATION

• A MEASURE OF HOW MUCH SOLUTE IS DISSOLVED IN A SPECIFIC AMOUNT OF SOLVENT OR SOLUTION

• MOLARITY (M)

• THE NUMBER OF MOLES OF SOLUTE DISSOLVED PER LITER OF SOLUTION

• M = MOLES OF SOLUTE / LITERS OF SOLUTION

DILUTIONS

• DILUTING A SOLUTION REDUCES THE NUMBER OF MOLES OF SOLUTE PER UNIT VOLUME, BUT THE TOTAL NUMBER OF MOLES OF SOLUTE IN SOLUTION DOES NOT CHANGE

• M1 V1 = M2 V2

• SEE EX P481

THE SOLVATION PROCESS

• DEPENDS ON THE FORCES BETWEENTHE SOLUTE PARTICLES AND THE FORCES BETWEEN THE SOLUTE ANDS OLVENT PARTICLES

• BONDING AND POLARITY IMPORTANT

• AS INDIVIDUAL SOLUTE IONS BREAKAWAY FROM THE CRYSTAL, THE NEGATIVELY AND POSITIVELYCHARGED IONS BECOME SURROUNDED BY SOLVENT MOLECULES AND THE IONIC CRYSTAL DISSOLVES

AQUEOUS SOLUTIONS

• HEAT OF SOLUTION

• THE OVERALL ENERGY CHANGE THAT OCCURS DURING THE SOLUTIONFORMATION PROCESS

• USUALLY EXOTHERMIC - RELEASES HEAT

to break apart the attractive forces in the solute and solvent heat is required so endothermic when the particles mix heat is released so exothermic

• IONIC

• MOST DISSOLVE IN WATER DUE TO ITS POLARITY

• CONDUCT ELECTRICITY

• MOLECULAR

• SOME DISSOLVE IN WATER, SOME DO NOT•

OIL AND WATER DO NOT MIX

• NON CONDUCTIVE

FACTORS THAT AFFECT SOLVATION

• AGITATION

• ALLOWS NEW COLLISIONS BETWEEN THE SOLUTE AND SOLVENT PARTICLES

• SURFACE AREA

• GREATER SURFACE AREA (SMALLER PIECES) ALLOWS MORE COLLISIONS TO OCCUR

• TEMPERATURE

• HIGHER TEMPS INC PARTICLE MOTION, MORE COLLISIONS

SOLUBILITY

• THE MAXIMUM AMOUNT OF SOLUTE THAT WILL DISSOLVE IN A GIVEN AMOUNT OFSOLVENT AT A SPECIFIC TEMPERATURE AND PRESSURE

• UNSATURATED SOLUTION

• CONTAINS LESS DISSOLVED SOLUTE FOR A GIVEN TEMP AND PRESS

.• CAN ADD MORE SOLUTE

• UNSWEET ICED TEA, ADD YOUR OWN AMOUNT OF SUGAR

• SATURATED SOLUTION

• CONTAINS THE MAX AMOUNT OF DISSOLVED SOLUTE FOR A GIVEN TEMP AND PRESS.

• SWEET TEA

• SUPERSATURATED SOLUTION

• CONTAINS MORE DISSOLVED SOLUTE THAN A SATURATED SOLUTION AT THE SAME TEMP

• TO MAKE, INC TEMP OF SATURATED SOLUTION, ADD MORE SOLUTE PARTICLES,THEN COOL SLOWLY

How rock candy is produced

SOLUBILITY OF GASES

• PRESSURE

• LITTLE EFFECT ON SOLIDS AND LIQUIDS, STRONGLY INFLUENCES GASES

• HENRY'S LAW

• SOLUBILITY IS DIRECTLY PROPORTIONAL TO PRESSURE

S1/P1 = S2/P2

Explains why soda goes flat after opening!

When you open the can the carbon dioxide gas that was dissolved in the liquid starts to escape in the air. This is because the pressure decreases.

ELECTROLYTES AND COLLIGATIVEPROPERTIES

• COLLIGATIVE PROPERTIES

• A PHYSICAL PROPERTY OF A SOLUTION THAT DEPENDS ON THE NUMBER, BUT NOT THE IDENTITY, OF THE DISSOLVED SOLUTE PARTICLES

• ELECTROLYTES

• AN IONIC COMPOUND WHOSE AQUEOUS SOLUTION CONDUCTS AN ELECTRIC CURRENT

4 examples of colligative properties

vapor pressure lowering,

boiling point elevation,

freezing point depression,

osmotic pressure

VAPOR PRESSURE LOWERING

• THE LOWERING OF THE VP OF A SOLVENT BY THE ADDITION OF A NONVOLATILE SOLUTE TO THE SOLVENT

• SLOWS EVAPORATION

more solute particles = lower VP

• EX - SPILLED CAN OF SODA

• AS THE WATER EVAPORATES, THE SODA BECOMES MORE SUGAR AND LESS WATER,UNTIL THE VAPOR PRESSURE OF THE WATER IS SO LOW THAT IT BARELY EVAPORATES. AS A RESULT, THE SPILLED SODA REMAINS STICKY FOR A LONG TIME

BOILING POINT ELEVATION

• THE TEMP DIFFERENCE BETWEEN A SOLUTION'S BP AND A PURE SOLVENT'S BP

• EX - PASTA MAKING,• ADD SALT AFTER THE WATER HAS BOILED, OTHERWISE IT TAKES LONGER TO BOIL!• SALT IS FOR TASTE ONLY

FREEZING POINT DEPRESSION

• THE DIFFERENCE IN TEMP BETWEEN A SOLUTION'S FP AND THE FP OF ITS PURE SOLVENT

EX - SALT ON THE ROADS WHEN IT SNOWS

• ALLOWS FOR THE ROADS NOT TO FREEZE IF TEMP REMAINS LOW

OSMOTIC PRESSURE

• OSMOSIS

• THE DIFFUSION OF A SOLVENT THROUGH A SEMIPERMEABLEMEMBRANE

• FROM LOW TO HIGH CONC

• THE PRESSURE CAUSED WHEN WATER MOLECULES MOVE INTO OR OUT OF A SOLUTION

FP and BP of a solution vs pure solvent

FP of a solution is always lower than that of a pure solvent

BP of a solution is always higher than that of a pure substance