SOLUBILITY CURVE by CJQZKa

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									SOLUTIONS
                   RECALL
             TYPES OF MIXTURES:

                 SUSPENSIONS
                   COLLOIDS
                  SOLUTIONS

All mixtures are physically combined and can be
  physically separated.
          DEFINITION

A solution is a homogeneous
mixture of two or more
substance in a single physical
state
            Parts of a solution

SOLUTE – the substance that is dissolved
SOLVENT- the substance that does the dissolving
          Definitions




Solute - KMnO4    Solvent - H2O
         TYPES OF SOLUTIONS

SOLUTE    SOLVENT   EXAMPLE
GAS       GAS       Air
GAS       LIQUID    Seltzer (CO2)
LIQUID    LIQUID    Antifreeze (ethyl glycol in water)
SOLID     LIQUID    Sea water ( salt in water)
GAS       SOLID     Charcoal filter (poisonous gases in
                    carbon)
LIQUID    SOLID     Dental filling (mercury in silver)
SOLID     SOLID     Sterling silver (copper in silver)
          SOLID SOLUTION
• Contain two or more metals called alloys
• Formed by melting the components and
  mixing them together and allowing them to
  cool
• Properties of alloys are different from the
  original component metals
                 TYPES OF ALLOYS
ALLOY              COMPONENT              USES
Babbitt            Tin, antimony, copper Bearings

Bell metal         Copper, tin            Bells
Coinage metals     Copper, tin, zinc      Coins
16 karat gold      Gold, copper, silver   Jewelry

Sterling           Silver, copper         Jewelry, flatware
Nichrome           Nickel, iron,          Heating elements
                   chromium,
                   manganese
         GASEOUS SOLUTIONS
• All mixture of gases
• Properties depend on the properties of its
  components
Example: Nitrogen in air serves as a gas that
  dilutes pure oxygen which is toxic to people
  and animals, and is very combustible.
             LIQUID SOLUTIONS
•   Most familiar type of solution
•   The solvent and the solution are liquids
•   Solute may be a gas, a solid, or a liquid
•   It is proper to describe liquids that are soluble
    to each other as MISCIBLE or can mix. And
    insoluble liquids as IMMISCIBLE. Or cannot
    mix. Example: alcohol is miscible in water
    while oil is immiscible in water.
       Important terminologies:
• Soluble – substance that dissolves another
  substance
• Insoluble – substance that does not dissolve
  another substance
• Miscible – liquids that are completely soluble
  in each other or can mix
• Immiscible – liquids that are not soluble in
  each other or cannot mix
         AQUEOUS SOLUTIONS
• Solutions with water as the solvent
• Aqueus, means like or containing water.
• Substances that dissolve in water are classified
  according to whether they produce ions or
  molecules in solution.
• Solutions that conduct electricity are called
  ELECTROLYTES.
SOLUBILITY
              Solubility
Solubility
  maximum grams of solute that will
  dissolve
  in 100 g of solvent at a given temperature
  varies with temp
  based on a saturated solution
Vitamins

 • Multi Vitamin
    – Provides many essential
      vitamins
    – “Expensive urine”
 • Water Soluble
    – Vitamin C
    – Must be replenished regularly
 • Fat Soluble
    – Can overdose
    – Vitamin A
    – Can be ingested periodically,
      stored in body fat
Supplements

     Steroids include estrogen, cortisol,
     progesterone, and testosterone.

     OIL SOLUBLE (NON POLAR)
                 Solubility
UNSATURATED      SATURATED            SUPERSATURATED
  SOLUTION        SOLUTION                 SOLUTION
  more solute   no more solute         becomes unstable,
   dissolves       dissolves              crystals form




                  increasing concentration
FACTORS AFFECTING SOLUBILITY
Factors Affecting Solubility

           Polarity

   Temperature

         Surface Area

       Stirring
NATURE OF SOLUTE AND SOLVENT
      There is a general saying that "like dissolves
  like" (but this is a very general rule, with many
  exceptions).
           “LIKE DISSOLVES LIKE”
 Refers to the type of bonding between separate
  molecules
 If the bonding between separate molecules of
  the substance to be dissolved is similar to the
  type of bonding between solvent molecules,
  there is a good chance that the substance will
  dissolve.
     Intramolecular Bonding
• Intramolecular bonding refers to the chemical
  bonding that holds atoms together within a
  molecule of a compound

   Covalent bonding and ionic bonding are the
  two main types of intramolecular bonding
Covalent bonding involves the sharing
 of valence electrons between two
 atoms. Eg. covalent bonding holds
 hydrogen and oxygen atoms together to
 form a water molecule, H2O.

 POLAR- unequal sharing of electrons
NON POLAR – equal sharing of electrons
COVALENT BONDING
• Ionic bonding involves the transfer of
  valence electrons from one atom to
  another.
• The electrostatic attraction between opposite
  charged ions holds the molecule (formula unit)
  together. An example is sodium chloride, NaCl,
  which involves the attraction between Na+ and
  Cl- ions.
IONIC BONDING
        Intermolecular Bonding

 Intermolecular bonding, on the other hand, is
  what holds two or more separate molecules
  together in the solid and liquid phases. What
  type of intermolecular bonding is involved
  largely depends on two main factors:
  1. whether the bonds within a single molecular are
     polar or not (an unequal distribution of charge
     between two atoms involved in a chemical bond due
     to an unequal sharing of electrons), and
  2. the overall shape of the molecule (it's molecular
     architecture - tetrahedral, linear, bent, etc.).
            POLAR MOLECULE

• A polar molecule will have one end of the
  molecule bearing a partial positive charge
  while another end carries a partial negative
  charge. Polar molecules must contain polar
  bonds.
The oxygen end of the molecule
has a partial negative charge (δ-),
while the hydrogen end is partially
positive (δ+).
 Water is an example of a highly polar molecule.
  Not only are the individual H—O bonds very polar
  (the shared electrons sit much closer to oxygen
  than to hydrogen, because oxygen has a higher
  electronegativity), but because the molecule has
  a bent shape the molecule itself is also polar. The
  oxygen end of the molecule has a partial negative
  charge (δ-), while the hydrogen end is partially
  positive (δ+).
 What holds one water molecule tightly to the
  next is the strong attraction between the δ+
  hydrogen end of one water molecule and the δ-
  end of a different molecule.
          NON POLAR MOLECULE

• Nonpolar molecules either have no positive
  and negative ends, because the bonds making
  up the molecule are nonpolar, or because the
  entire outer "edge" is negative while the core
  of the molecule is positive (or vice versa), thus
  having no oppositely charged ends.
SOLUTE     POLAR       NONPOLAR
           SOLVENT     SOLVENT


Ionic      Soluble     Insoluble

Polar      Soluble     Insoluble

Nonpolar   Insoluble   soluble
     The Effect of Temperature on
               Solubility
• Generally, increasing the temperature will
  increase solubility of solids and liquids.

• But increasing temperature will lower the
  solubility of gases (the gas will escape from
  solution, going back to the gas phase).
        The Effect of Pressure on the
             Solubility of Gases

• Pressure has no effect in the solubility of solids
  and liquids but has a strong effect on the
  solubility of gases.
• The solubility of gases increases when the
  pressure above the gas is increased. In other
  words, more gas will dissolve when pressure is
  increased. This is known as HENRY’S LAW
  (William Henry, English chemist).
                      Stirring

• Agitation increases the solubility of solid
  solute particles in a solvent.
                  Solubility

• Solids are more soluble at...
  – high temperatures.

              Gases are more soluble at...
                      • low temperatures &
                      • high pressures
                        (Henry’s Law).
                      • EX: nitrogen narcosis,
                        the “bends,” soda
                                                                                                                                      Solubility vs. Temperature for Solids
                                                                                                                                140
                                                                                                                                          KI
                                                                                                                                130

                                                                                                                                120

                                                                                                                                                 NaNO3                  gases

               Solubility
                                                                                                                                110




                                                                                       Solubility (grams of solute/100 g H2O)
                                                                                                                                                                        solids
                                                                                                                                100
                                                                                                                                                                KNO3
                 Table                                                                                                          90

                                                                                                                                80
                                                                                                                                                HCl               NH4Cl
             shows the dependence                                                                                               70

          of solubility on temperature                                                                                          60              NH3                    KCl
                                                                                                                                50

                                                                                                                                40

                                                                                                                                30
                                                                                                                                                         NaCl     KClO3
                                                                                                                                20

                                                                                                                                10
                                                                                                                                                          SO2

                                                                                                                                      0   10 20 30 40 50 60 70 80 90 100
LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 517
   How to determine the solubility of a given
                 substance?
• Find out the mass of solute needed to make a
  saturated solution in 100 cm3 of water for a
  specific temperature(referred to as the solubility).

• This is repeated for each of the temperatures
  from 0ºC to 100ºC. The data is then plotted on a
  temperature/solubility graph,and the points are
  connected. These connected points are called a
  solubility curve.
     How to use a solubility graph?
A.     IDENTIFYING A SUBSTANCE ( given the
     solubility in g/100 cm3 of water and the
     temperature)


• Look for the intersection of the solubility
  and temperature intersect at.
Example: What substance
 has a solubility of 90 g/100
 cm 3 of water at a

 temperature of 25ºC ?
Example:

What substance has a
solubility of 200 g/100 cm 3

of water at a temperature of
90ºC ?
B.   Look for the temperature or solubility


•Locate the solubility curve needed and
see for a given temperature, which
solubility it lines up with and visa versa.
• What is the
  solubility of
  potassium
  nitrate at
  80ºC ?
At what
  temperature
  will sodium
  nitrate have
  a solubility
  of 95 g/100
  cm3 ?
    At what
temperature
will potassium
iodide have a
solubility of
230 g/100 cm3
?
• What is the
  solubility of
  sodium
  chloride at
  25ºC in 150
  cm3 of water ?

 • From the
   solubility graph
   we see that
   sodium
   chlorides
   solubility is 36
   g.
Place this in the proportion below and solve for
the unknown solubility. Solve for the unknown
quantity by cross multiplying.
         Solubility in grams = unknown solubility in grams

           100 cm3 of water     other volume of water


         ___36 grams____ = unknown solubility in grams

           100 cm3 of water     150 cm3 water


   The unknown solubility is 54 grams. You can use this
   proportion to solve for the other volume of water if you're given
   the other solubility.
   C.    Determine if a solution is saturated,
         unsaturated,or supersaturated.
• If the solubility for a given substance places
it anywhere on it's solubility curve it is
saturated.
• If it lies above the solubility curve, then it's
supersaturated,
• If it lies below the solubility curve it's an
unsaturated solution. Remember though, if
the volume of water isn't 100 cm3 to use a
proportion first as shown above.
      Solubility  how much solute dissolves in a given amt.
      of solvent at a given temp.


SOLUBILITY
  CURVE                                           KNO3 (s)

                                                      KCl (s)
             Solubility
          (g/100 g H2O)



                                                     HCl (g)

                                Temp. (oC)

unsaturated:          solution could hold more solute; below line
saturated:            solution has “just right” amt. of solute; on line
supersaturated:       solution has “too much” solute dissolved in it;
above the line
   Solids dissolved in liquids   Gases dissolved in liquids



Sol.                             Sol.


            To                               To

       As To , solubility               As To , solubility
   Sometimes you'll need to determine
how much additional solute needs to be
added to a unsaturated solution in
order to make it saturated.

    For example,30 grams of potassium
nitrate has been added to 100 cm3 of
water at a temperature of 50ºC.
How many
additional grams
of solute must be
added in order to
make it
saturated?


From the graph
you can see that
the solubility for
potassium nitrate
at 50ºC is 84
grams
    If there are already 30 grams
of solute in the solution, all you
need to get to 84 grams is 54
more grams ( 84g-30g )
                                                                                                                                      Solubility vs. Temperature for Solids
                                                                                                                                140
                                                                                                                                          KI
                                                                                                                                130

                                                                                                                                120

                                                                                                                                                 NaNO3                  gases

               Solubility
                                                                                                                                110




                                                                                       Solubility (grams of solute/100 g H2O)
                                                                                                                                                                        solids
                                                                                                                                100
                                                                                                                                                                KNO3
                 Table                                                                                                          90

                                                                                                                                80
                                                                                                                                                HCl               NH4Cl
             shows the dependence                                                                                               70

          of solubility on temperature                                                                                          60              NH3                    KCl
                                                                                                                                50

                                                                                                                                40

                                                                                                                                30
                                                                                                                                                         NaCl     KClO3
                                                                                                                                20

                                                                                                                                10
                                                                                                                                                          SO2

                                                                                                                                      0   10 20 30 40 50 60 70 80 90 100
LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 517
                                                                                    Solubility vs. Temperature for Solids
                                                                                  140
                                                                                        KI
      Classify as unsaturated,                                                    130
      saturated, or supersaturated.                                               120

                                                                                  110        NaNO3                  gases




                                         Solubility (grams of solute/100 g H2O)
                                                                                                                   solids
                                                                                  100
                                                                                                            KNO3
                                                                                  90
      80 g NaNO3 @ 30oC =unsaturated
                                                                                  80
per                                                                                          HCl              NH4Cl
100   45 g KCl @ 60oC     =saturated
                                                                                  70

 g                                                                                60         NH3                   KCl
 H2
 O    50 g NH3 @ 10oC =unsaturated                                                50

                                                                                  40

      70 g NH4Cl @ 70oC =supersaturate                                            30
                                                                                                     NaCl    KClO3
                        d
                                                                                  20

                                                                                  10
                                                                                                     SO2

                                                                                    0   10 20 30 40 50 60 70 80 90 100
                                                                                                     Solubility vs. Temperature for Solids
                                                                                               140
                                                                                                       KI
                                                                                               130

                                                                                               120
Per 500 g H2O, 120 g KNO3 @ 40oC
                                                                                               110              NaNO3                  gases

                                                                                                                                       solids




                                                      Solubility (grams of solute/100 g H2O)
                                                                                               100
                                                                                                                               KNO3
saturation point @ 40oC for 100 g H2O = 66 g KNO3                                              90

                                                                                               80
                                                                                                               HCl               NH4Cl
                                                                                               70
So sat. pt. @ 40oC for 500 g H2O = 5 x 66 g = 330 g
                                                                                               60             NH3                     KCl
                                                                                               50

                                                                                               40


 120 g < 330 g          unsaturated                                                            30
                                                                                                                        NaCl     KClO3
                                                                                               20

                                                                                               10
                                                                                                                         SO2

                                                                                                         0   10 20 30 40 50 60 70 80 90 100
Describe each situation below.



        (A) Per 100 g H2O, 100 g     Unsaturated; all solute
        NaNO3 @ 50oC.                dissolves; clear solution.



        (B) Cool solution (A) very   Supersaturated; extra
        slowly to 10oC.              solute remains in solution;
                                     still clear.




      (C) Quench solution (A) in     Saturated; extra solute
       an ice bath to 10oC.          (20 g) can’t remain in
                                     solution, becomes visible.
1. a. 80 g     b.   42 g

2. b. 42 g KNO3 = 25g KNO3 = 60 g
      100 g H2O x g H2O
3. a. 7.7 mg at 30oC
   b. 9.2 mg 20oC

4. 9.2 mg O2 = x mg O2
   1,000 g H2O 1,000 g H2O=
   =0.92 mg O2
Nosce te ipsum

								
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