TOPICS TO BE COVERED1.WHAT ARE SOLUTIONS?2.SOLVENTS AND SOLUTES3.SOLUBILITY AND ITS FACTORS4.CONCENTRATIONS5.SOLUTION STOICHIOMETRY6.COLLIGATIVE PROPERTIES
SOLUTIONSCHEMICALS + WATER
1. WHAT ARE SOLUTIONSOBJECTIVE: WHAT ARE THEY?
SOLUTIONS• IMPORTANCE OF STUDYING SOLUTIONS
• BECAUSE MANY REACTIONS TAKE PLACE IN SOLUTIONS
• BECAUSE MIXING REACTANTS IN SOLID FORM OFTEN DO NOT RESULT IN REACTIONS.
• REACTIONS REQUIRE COLLISIONS AT THE ATOMIC/MOLECULAR LEVEL, AND IN THE SOLID STATE, THIS DOES NOT OCCUR AT A SIGNIFICANT RATE.
1. WHAT ARE SOLUTIONS?SOLUTIONS ARE…
HOMOGENOUS MIXTURES
• HOMOGENOUS VS. HETEROGENEOUS• MIXTURE VS. COMPOUND
1. WHAT ARE SOLUTIONS?
HOMOGENEOUS
EVEN DISTRIBUTION
HETEROGENEOUS
UNEVEN DISTRIBUTION
1. WHAT ARE SOLUTIONS?
MIXTURES
PHYSICALLY MIXED
COMPOUND
CHEMICALLY JOINED
SOLUTIONS
1. WHAT ARE SOLUTIONS?
MIXTURES
CAN BE SEPARATED
COMPOUND
CANNOTBE SEPARATED
1. WHAT ARE SOLUTIONS?
MIXTURES
CAN BE SEPARATED
COMPOUND
CANNOTBE SEPARATED
1. WHAT ARE SOLUTIONS?SOLUTIONS ARE…
HOMOGENOUS MIXTURES
SOLUTIONS = TWO OR MORE THINGS EVENLY MIXED TOGETHERSOLUTIONS = THINGS MIXED INTO WATER
1. WHAT ARE SOLUTIONS?HETEROGENEOUS MIXTURES:
SUSPENSIONS & COLLOIDS
Suspensions
Separates and Settles Colloids do not
Jello or Milk
2. SOLUTES AND SOLVENTSOBJECTIVE: CLASSIFYING INGREDIENTS IN
SOLUTIONS
2. SOLVENT AND SOLUTEAll solutions have at least TWO ingredients
Ingredients can be classified as either a
SOLVENTSOLUTE
2. SOLVENT AND SOLUTE
SOLVENT- PRESENT IN GREATER AMOUNT
- DOES THE “DISSOLVING”
WATER IS THE UNIVERSAL SOLVENT
SOLUTE- PRESENT IN LESSER AMOUNT
- IS THE ONE “DISSOLVED”
2. SOLVENT AND SOLUTE
Does not always involve liquids
2. SOLVENT AND SOLUTECAN THERE BE MORE THAN ONE SOLUTE IN A
SOLUTION?
CAN THERE BE MORE THAN ONE SOLVENT IN A SOLUTION?
IF A SOLUTION IS A MIXTURE, DO THE SOLUTES AND THE SOLVENTS CHEMICALLY REACT OR PHYSICALLY MIX?
3. SOLUBILITYOBJECTIVE: IF SOMETHING DOES OR DOES NOT
DISSOLVE
3. SOLUBILITY
Why do some things dissolve while others do not?
What does it mean for something to “dissolve?”
3. SOLUBILITYWhy do some things dissolve
while others do not?
“Like dissolves Like”
3. SOLUBILITY
“Like dissolves Like”Polar Solvent will dissolve…
Non-Polar Solvent will dissolve
3. SOLUBILITY
Miscible vs. ImmiscibleMiscible = dissolves
Immiscible = does NOT dissolve
3. SOLUBILITY
What does it mean for something to “dissolve?”
It means to “dissociate”
Dissociation
Separating
dipoles
3. SOLUBILITYNow we know why some
things dissolve and others do not.
We also know what it means for something to dissolve.
3. SOLUBILITYHow much of some thing can
be dissolved?
SolubilityTHE MAXIMUM AMOUNT OF A SOLUTE THAT CAN DISSOLVE
AT A SPECIFIED TEMPERATURE AND PRESSURE
3. SOLUBILITY
Increasing/Decreasing Solubility
1. Temperature2. Pressure
3. SOLUBILITY
WHAT IS THE
TREND?
SO AS TEMPERATUR
E _______, SOLUBILITY
______
3. SOLUBILITY
Increasing Solubility with Temperature
Unsaturated Solutions
more solute can be
dissolved
no heat necessary
Saturated Solutions
no more solute can be
dissolvedno heat necessary
Super-Saturated Solutions
more solute than normal
heat necessary
Super-Saturated Solutions
Rock Candy
GAS SOLUTEAS TEMPERATURE _____ THE SOLUBILITY OF GAS _______.
SO TEMPERATURE AND SOLUBILITY OF A GAS HAVE
A(N) ____.
RECALLING HEAT AS KINETIC ENERGY, WE CAN EXPLAIN
THIS BY…
SOLUBILITY OF SOLIDS
SOLUBILITY OF GASES
1. EXPLAIN WHY THERE MIGHT BE MORE MINERAL FORMATION SURROUNDING THERMAL SPRINGS THAN COOL MOUNTAIN SPRINGS.
2. WHY DOES WARM SODA FLAT FASTER THAN COLD SODA?
3. ON SAME SHEET, ANSWER QUESTIONS #67-72 ON PG 491.
4. TURN IN
4. CONCENTRATIONSOBJECTIVE: MEASURING SOLUBILITY
4. CONCENTRATION
Concentration = how much solute in the
solution2 methods
4. CONCENTRATIONMolarity MOLALITY
Symbol MFormula
M = mol L
Units mol = mol of SOLUTE
L = liters of solution
Example
5 M, or 5 molar
BA(NO3)2(AQ) + NA2SO4(AQ) BA(SO4)(S) + 2NANO3(AQ)
• 25ML OF 0.5M BA(NO3)2 SOLUTION IS COMBINED WITH EXCESS NA2SO4. HOW MANY GRAMS OF PRECIPITATE ARE FORMED?
CACL2(AQ) + 2NH4OH(AQ) CA(OH)2(S) + 2NH4CL(AQ)
• HOW MANY ML OF A 0.2M NH4OH SOLUTION WOULD BE REQUIRED TO PRECIPITATE ALL OF THE CA2+ IONS IN 50ML OF A 0.15M CACL2 SOLUTION?
PB(NO3)2(AQ) + 2NACL(AQ) PBCL2(S) + 2NANO3(AQ)
• HOW MANY GRAMS OF PRECIPITATE WOULD FORM IF 30ML OF A 0.25M PB(NO3)2 SOLUTION WAS ADDED TO 20ML OF A 0.50M NACL SOLUTION?
• HOW MANY MOLES OF THE EXCESS REACTANT ARE LEFT OVER AFTER THE REACTION?
• WHAT IS THE MOLARITY OF THE EXCESS REACTANT AFTER THE REACTION?
CAN A SOLUTION WITH UNDISSOLVED SOLUTE BE
SUPERSATURATED?
• SOLUBILITY OF GASES
• HENRY’S LAW• A GAS HAS A SOLUBILITY OF 3.6G/L AT A PRESSURE OF 100KPA. WHAT PRESSURE IS NEEDED TO PRODUCE AN AQUEOUS SOLUTION CONTAINING 9.5G/L OF THE SAME GAS?
• THE SOLUBILITY OF METHANE IN WATER AT 100KPA IS 0.026G/L, WHAT WILL THE SOLUBILITY BE AT A PRESSURE OF 180KPA?
• SOLUBILITY OF LIQUIDS
• LIKE DISSOLVES LIKE• MISCIBLE – DESCRIBES TWO OR MORE
LIQUIDS THAT ARE ABLE TO DISSOLVE INTO EACH OTHER
• IMMISCIBLE – DESCRIBES TWO OR MORE LIQUIDS THAT DO NOT MIX WITH EACH OTHER
• SOLUBILITY OF LIQUIDS
• LIKE DISSOLVES LIKE• MISCIBLE
• NON-POLAR AND NON-POLAR = MISCIBLE
• POLAR + POLAR = MISCIBLE
• IMMISCIBLE • NON-POLAR + POLAR = IMMISCIBLE
• MAKING SOLUTIONS
• HOW WOULD YOU PREPARE A 100ML OF 0.40M MGSO4 FROM A STOCK SOLUTION OF 2.0M MGSO4?
• YOU NEED 250ML OF 0.20M NACL. WHAT VOLUME WOULD YOU NEED FROM A STOCK 1.0M NACL SOLUTION?
• MAKING SOLUTIONS
• AN EXPERIMENT REQUIRES 1L OF 1.0M KOH. YOU HAVE 1L OF 0.5M KOH. CAN YOU PREPARE THE REQUIRED SOLUTION BY DILUTING WHAT YOU HAVE?
• PERCENT SOLUTIONS
• SIMILAR TO PPM
• PERCENT SOLUTIONS
• WHAT IS THE PERCENT BY VOLUME OF ETHANOL (C2H6O) WHEN 75ML OF ETHANOL IS DILUTED TO A VOLUME OF 250ML WITH WATER?
• A SOLUTION CONTAINS 2.7G OF CUSO4 IN 75ML OF SOLUTION. WHAT IS THE PERCENT BY MASS OF THE SOLUTION?
• CONCENTRATION OF IONS
• CALCULATE THE NUMBER OF MOLES OF CL- IN 2.75 L OF 1.0X10-3M ZNCL2
• HOW MANY GRAMS OF SULFATE ION ARE PRESENT IN 500ML OF A 2M AL2(SO4)3 SOLUTION?
• COLLIGATIVE PROPERTIES
• THE PHYSICAL PROPERTIES OF A SOLUTION ARE DIFFERENT FROM THOSE OF A PURE SOLVENT.
• SOME OF THESE DIFFERENCES ARE DUE TO THE PRESENCE OF SOLUTE PARTICLES IN THE SOLUTION.
• COLLIGATIVE PROPERTIES
• COLLIGATIVE PROPERTIES – A PROPERTY OF A SOLUTION THAT DEPENDS ON THE CONCENTRATION OF THE SOLUTE PARTICLES.
• THE WORD COLLIGATIVE IS DERIVED FROM THE LATIN COLLIGATUS MEANING BOUND TOGETHER, SINCE THESE PROPERTIES ARE BOUND TOGETHER BY THE FACT THAT THEY ALL DEPEND ON THE NUMBER OF SOLUTE PARTICLES.
• COLLIGATIVE PROPERTIES
• BOILING POINT ELEVATION – THE DIFFERENCE IN TEMPERATURE BETWEEN THE BOILING POINTS OF A SOLUTION AND OF THE PURE SOLVENT.
• FREEZING POINT DEPRESSION – IS THE DIFFERENCE IN TEMPERATURE BETWEEN THE FREEZING POINTS OF A SOLUTION AND OF THE PURE SOLVENT.
• COLLIGATIVE PROPERTIES
• THE MAGNITUDE OF BP ELEVATION AND FP DEPRESSIONS IS PROPORTIONAL TO THE NUMBER OF SOLUTE PARTICLES DISSOLVED IN THE SOLVENT.
• COLLIGATIVE PROPERTIES
• WOULD A DILUTE OR CONCENTRATED SODIUM FLUORIDE SOLUTION HAVE A HIGHER BOILING POINT?
• IF EQUAL NUMBER OF MOLES OF KI AND MGF2 ARE DISSOLVED IN EQUAL AMOUNTS OF WATER, WHICH SOLUTION WOULD HAVE THE HIGHEST:
• BOILING POINT• FREEZING POINT
MOLARITY MOLALITY
• VOLUME OF SOLUTE + • VOLUME OF SOLVENT
• UNIT = M
BOTH MOLARITY AND MOLALITY MEASURE CONCENTRATION
• MASS OF SOLVENT IN KILOGRAMS
• UNIT = M (ITALICIZED)
• CALCULATING MOLALITY
• CALCULATE THE MOLALITY AND TOTAL MOLALITY (IF APPLICABLE) OF A SOLUTION PREPARED BY DISSOLIVING 10.0G OF NACL IN 600 G OF WATER.
• CALCULATE THE MOLALITY AND TOTAL MOLALITY (IF APPLICABLE) OF A SOLUTION PREPARED BY DISSOLIVING 10.0G C12H22O11 OF IN 600 G OF WATER.
• CALCULATING MOLALITY
• HOW MANY GRAMS OF POTASSIUM IODIDE MUST BE DISSOLVED IN 500G OF WATER TO PRODUCE A 0.060 MOLAL KI SOLUTION?
• CALCULATING MOLALITY
• WHAT IS THE DIFFERENCE BETWEEN A 1M AND A 1M SOLUTION?
• A 4 G SUGAR CUBE (C12H22O11) IS DISSOLVED IN A 350 ML TEACUP OF 80 °C WATER. WHAT IS THE MOLALITY OF THE SUGAR SOLUTION IF THE DENSITY OF WATER AT 80° = 0.975 G/ML
• CALCULATING BP AND FP CHANGES
• BP
•ΔTB = KB * M
• FP
•ΔTF = KF * M
• CALCULATING BP AND FP CHANGES
• KB, KF = THE MOLAL BP/FP CONSTANT, WHICH IS EQUAL TO THE CHANGE IN BP/FP TEMPERATURE FOR A 1 MOLAL SOLUTION.
• CALCULATING BP AND FP CHANGES
• WHAT IS THE BOILING POINT OF A 1.5 MOL SOLUTION THAT IN 800G OF WATER?
• CALCULATING BP AND FP CHANGES
• WHAT IS THE BOILING POINT OF A 1.2 MOL SOLUTION OF NACL IN 800G OF WATER?
• CALCULATING BP AND FP CHANGES• WHAT IS THE BP AND FP OF A 1.40 MOL
SOLUTION OF NA2SO4 IN 1750G OF WATER?
• DETERMINING MOLAR MASS FROM ΔTB
AND ΔTF
• MOLAR MASS =
• 7.5 G OF SOLUTE IS ADDED TO 22.60 G OF WATER. THE WATER BOILS AT 100.78 DEGREES C. WHAT IS THE MOLAR MASS OF THE SOLUTE?
• DETERMINING MOLAR MASS FROM ΔTB AND ΔTF
• WHAT INFORMATION/MEASUREMENTS ARE NEEDED TO FIND THE MOLAR MASS OF A SOLUTE WHEN GIVEN THE BOILING POINT ELEVATION, ΔTB, FOR AN AQUEOUS SOLUTION?