Discusses the properties of electrolytes and non electrolytes. Also freezing point depression and boiling point elevations. Solved problems are included. **More good stuff available at: www.wsautter.com and http://www.youtube.com/results?search_query=wnsautter&aq=f

1. Copyright Sautter 2015

2. SOLUTIONS & CONCENTRATIONS
• WHAT IS A SOLUTION ?
• WHAT IS CONCENTRATION & HOW IS
IT MEASURED ?
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3. IS DISSOLVING A CHEMICAL OF A PHYSICAL
PROCESS ?
• IF SUGAR IS DISSOLVED IN WATER IS ITS CHEMICAL
NATURE CHANGED ?
• NO !!
• IF THE SOLUTION IS DRIED, A WHITE, SWEET
CRYSTALLINE SUBSTANCE (SUGAR) IS OBSERVED.
• THEREFORE DISSOLVING IS A PHYSICAL CHANGE. THE
CHEMICAL PROPERTIES OF A SUBSTANCE MUST BE
CHANGED IN ORDER FOR A CHEMICAL CHANGE TO
OCCUR !
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4. A SOLUTION THEN IS THE RESULT OF THE
PHYSICAL CHANGE CALLED DISSOLVING, BUT
PRECISELY, WHAT IS A SOLUTION?
• THE OPPPOSITE OF A SOLUTION IS A SUSPENSION.
• MUDDY WATER IS A SUSPENSION.
• SUGAR DISSOLVED IN WATER IS A SOLUTION.
• CAN YOU NAME SOME DIFFERENTS BETWEEN THEM?
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5. SOME OBSERVED DIFFERENCES
• DIFFERENCES IN CLARITY !
• DIFFERENCES IN UNIFORMITY !
• DIFFERENCES IN SETTLING !
• DIFFERENCES IN FILTRATION !
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6. CLARITY
• SOLUTIONS ARE TRANSPARENT *
• SUSPENSIONS ARE OPAQUE *
• * ALTHOUGH SOLUTIONS ARE TRANSPARENT (YOU CAN SEE THROUGH
THEM) THEY MAY BE COLORED
• * OPAQUE MEANS CLOUDLY
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7. UNIFORMITY
• UNFORMITY OR HOMOGENOUS MEANS THE SAME
THROUGHOUT
• SOLUTIONS ARE HOMOGENOUS ( THE SAME AMOUNT OF
DISSOLVED SUBSTANCE FOR THE SAME AMOUNT OF
SOLUTION EVERYWHERE IN THE SYSTEM)
• SUSPENSIONS ARE HETEROGENOUS (THE AMOUNT OF
SUSPENSED MATERIAL DIFFERS FROM PLACE TO PLACE)
• FOR EXAMPLE, THE AMOUNT OF MUD IS MORE
CONCENTRATED AT THE BOTTOM THAN AT THE TOP
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8. SETTLING OUT
• SOLUTIONS NEVER SETTLE. THE
DISSOLVED MATERIAL WILL NOT FALL
OUT OF THE SOLUTION (UNLESS THE
TEMPERATURE IS CHANGED)
• IN SUSPENSIONS, EVENTUALLY THE
SUSPENDED MATERIAL WILL FALL TO
THE BOTTOM OF THE CONTAINER !
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9. FILTRATION
• THE DISSOLVED MATERIAL IN A
SOLUTION CANNOT BE FILTERED OUT BY
ORDINARY MEANS (FOR EXAMPLE THE
SALT CANNOT BE FILTERED FROM SEA
WATER WITH FILTER PAPER)
• IN A SUSPENSION SUCH A MUDDY WATER,
THE SUSPENDED SUBSTANCE CAN BE
FILTERED LEAVING A CLEAR LIQIUD
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10. SOLUTIONS VS. SUPSENSIONS
• SOLUTIONS
• (1) TRANSPARENT
• (2) HOMOGENOUS
• (3) WILL NOT SETTLE OUT
• (4) CANNOT BE FILTERED
• SUSPENSIONS
• (1) OPAQUE
• (2) HETEROGENOUS
• (3) WILL SETTLE OUT
• (4) CAN BE FILTERED
FOG
COLLOIDAL
SUSPENSION 10

11. WHAT IS A SOLUTION ?
• DEFINITION: A SOLUTE DISSOLVED IN A
SOLVENT (FOR EXAMPLE A SUGAR / WATER SOLUTION)
• SOLUTE IS THE DISSOLVED SUBSTANCE (THE SUGAR)
• SOLVENT IS THE DISSOLVING MEDIUM IN WHICH
THE SOLUTE IS DISSOLVED (THE WATER)
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12. WHAT COMBINATION OF PHASES CAN FORM
SOLUTIONS ?
• THINK OF SOME DIFFERENT KINDS OF SOLUTIONS. THEY MUST
HAVE THE PROPERTIES OF SOLUTIONS TO BE CONSIDERED.
• SOME COMMON COMBINATIONS: SOLID SOLUTE / LIQUID SOLVENT
(SUGAR DISSOLVED IN WATER)
• LIQUID SOLUTE / LIQUID SOLVENT (ANTIFREEZE DISSOLVED IN
WATER)
• GAS SOLUTE / LIQUID SOLVENT (SODA WATER – CARBON DIOXIDE
DISSOLVED IN WATER)
• GAS SOLUTE / GAS SOLVENT ( AIR – OXYGEN DISSOLVED IN
NITROGEN)
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13. WHAT ARE THE GENERAL CLASSIFICATIONS OF SOLUTIONS ?
• THERE ARE GENERALLY TWO TYPES:
ELECTROLYTES AND NON ELECTROLYTES
• ELECTROLYTIC SOLUTIONS ARE ELECTRICALLY
CONDUCTIVE. THEY CONSIST OF IONIC SOLUTES
DISSOLVED IN POLAR SOLVENTS
• NON ELECTROLYTIC SOLUTIONS ARE NON
CONDUCTIVE AND THEY CONSIST OF
MOLECULAR SOLUTES DISSOLVED IN NON
POLAR SOLVENTS.
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15. TYPES OF ELECTROLYTIC SOLUTIONS
• STRONG ELECTROLYTES
• SOLUTIONS IN WHICH ALL OF THE DISSOLVED
SOLUTE FORMS IONS
• WEAK ELECTROLYTES
• SOLUTIONS IN WHICH ONLY A PERCENTAGE OF
THE DISSOLVED SOLUTE FORMS IONS
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16. OTHER WAYS TO CLASSIFY SOLUTIONS
• SATURATED SOLUTIONS
• NO MORE SOLUTE CAN BE DISSOLVED
(SOLUBILITY LIMIT HAS BEEN REACHED)
• UNSATURATED SOLUTIONS
• ADDITIONAL SOLUTE CAN STILL BE DISSOLVED
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17. WHAT DETERMINES THE SATURATION
POINT OF A SOLUTION ?
• (1) THE TYPE OF SOLUTE AND SOLVENT
USED
• (2) THE TEMPERATURE OF THE SOLUTION
(Generally solids dissolve better at higher
temperatures while gases dissolve more poorly)
• (3) GAS PRESSURE WHEN A GAS IS THE
SOLUTE (HENRY’S LAW)*
• *THE SOLUBILITY OF A GAS IS DIRECTLY
RELATED TO THE PRESSURE OF THAT GAS
ABOVE THE SOLUTION
• Solubility = a constant x Pressure of the gas 17

18. How Temperature Effects Solubility
Note that all substances (even solids), do not dissolve
better at higher temperatures although most do.
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19. HOW CAN THE SOLUTIONS COMPOSED OF THE
SAME SUBSTANCES BE DIFFERENT ?
• FOR EXAMPLE, HOW CAN ONE AQUEOUS* SUGAR
SOLUTION BE DIFFERENTIATED FROM ANOTHER ?
• DIFFERENT SOLUTIONS CONSISTING OF THE SAME
SOLUTE / SOLVENT COMBINATIONS MAY BE
DIFFERENT IN CONCENTRATION !
• WHAT DOES CONCENTRATION MEAN ??
• * AQUEOUS MEANS THAT WATER IS THE SOLVENT
MEDIUM IN THE SOLUTION
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20. CONCENTRATION
• CONCENTRATION REFERS TO A RATIO OF SOLUTE
AMOUNT TO SOLVENT OR SOLUTION AMOUNT.
• FOR EXAMPLE, CONCENTRATED ORANGE JUICE
MEANS THAT THE SOLUTE (THE ORANGE
COMPONENT) IS PRESENT IN LARGE QUANTITY
RELATIVE TO THE SOLVENT (THE WATER
COMPONENT).
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