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     TAKS OBJ 3 QUIZ
     NOTES MIXTURES,
 SOLUTIONS, and SOLUBILITY
MATTER

   WHAT IS MATTER?
Atoms are matter

• Carbon is an element
• Elements are made of atoms
• Diamonds are made of atoms of
  the element Carbon
• Foil is made of the atoms of the
  element Aluminum.
Atoms are matter
• Elements most abundant in the
  earth and human body are:
Element
• Pure substance that consists
  entirely of one type of atom



• Hydrogen                sulfur   magnesium
  COMPOUNDS
• 2 or more elements combine
  to make a compound

• Nylon is an example of a
  compound
  • Nylon contains atoms of Carbon,
   Hydrogen, Nitrogen, and Oxygen,
   but each strand actually contains
   hundreds of these units linked
   together.
Compounds…

• Compounds are different from
  the elements in which they
  contain.
Molecules

• Smallest unit of a substance
  that exhibits all of the
  properties characteristic of that
  substance


• They act as a unit
  • Example: water H2O
Molecules

• Most molecules are made of
  atoms of different elements, but
  some can be made of atoms of
  the same element.
Pure Substance

• Any matter that has a fixed
  composition and definite
  properties

• In Chemistry, a pure
  substance is MATTER WITH
  A FIXED COMPOSITION AND
  DEFINITE PROPERTIES
Pure Substance
vs. Mixture

• When people say “Pure Grape
  Juice” this means it contains
  only the juice of the grapes with
  NOTHING added or taken away

• In reality, grape juice is NOT a
  pure substance. It is a
  MIXTURE!!!
Mixture
• A combination of more than one
  substance
 • Grape juice is a mixture because it
   contains water, sugars, acids, and
   vitamins
 • The composition of grape juice is
   not fixed; it can have different
   amounts of water, sugars, or other
   compounds
Mixtures vs.
Pure Substances

• Almost all things we eat are
  mixtures
• The air we breathe is a mixture of
  nitrogen and oxygen

• Pure Substance: (ex: water)
  • Cannot be broken down by physical
    actions such as boiling, melting, or
    grinding
Pure substances blended
together make mixtures
• A mixture may have some
  properties similar to the pure
  substances that make it
• Although you cannot see the
  different substances in grape
  juice, the mixture has chemical
  and physical properties in
  common with its components
    • Ex: fluid like water; sweet like sugar
Mixtures

• There are 2 types of
  mixtures that we will
  deal with:
  • Heterogeneous mixture
  • Homogenous mixture
 Heterogeneous
 Mixtures
• Mixtures of this type are not
  the same throughout.
  • Example: Fruit Salad
    • Each spoonful of fruit salad would
      give you a different variety – no 2
      spoonfuls would be exactly the
      same.
 Homogenous
 Mixtures

• These mixtures are uniform,
  in that no matter where you
  get your sample from in the
  mixture – each sample will
  be the exact same.
homogeneous   heterogeneous
Mixtures classified
by how thoroughly
the substances mix
Solids + Liquids
    examples to compare:
          Salt + water
             vs
        Flour + water
Mixtures classified by how
thoroughly the substances mix

• Flour doesn’t mix very well with
  water- it gives a cloudy white
  mixture The flour doesn’t
  dissolve in water
    This is an example of a
    heterogeneous mixture
    because the substances
    are not uniformly mixed.
Mixtures
Salt + Water
  You cannot see the salt and
  the mixture is clear

  WHY??
       −SALT DISSOLVES IN WATER
  Even if you leave the mixture
  for a long time, the salt will
  not settle out.
     This is an example of a:
    homogenous mixture
    Mixing between the individual
    units and is the same throughout.
Obj. 1 cont…
Pure or Mixture?!?!
                  mixture
 1. Kool-aid
                         pure
 2. distilled water
 3. tap water         mixture

 4. chocolate chip cookie        mixture

 5. oxygen gas        pure

 6. atmosphere         mixture

 7. Glucose (C6H12O6)        pure
CLASSIFYING MATTER

                      Elements
         Pure
         Substance
                      Compounds
MATTER
                     Homogeneous
         Mixtures


                     Heterogeneous
Solutions and
Homogenous mixtures

  SOLUTIONS & HOMOGENOUS
  MIXTURES are synonymous.

   Homogenous mixtures are mixed
   completely, all the way down to
   their most fundamental particles-
   atoms, molecules, or ions.
  Mixtures

• Gasoline is a liquid
  mixture…
    • A homogenous mixture of at
      least 100 compounds in various
      quantities
    • The compounds within gasoline
      are miscible, thus gasoline
      looks like a pure substance
      even though it is not.
MISCIBLE

      Describes 2 or more
      liquids that are able to
      dissolve into each other in
      various proportions

                Ex: Water and
               Rubbing alcohol
IMMISCIBLE

• If you shake a mixture of oil and
  water, the water will settle out
  after a while.
• Oil and water form a
  heterogeneous mix
• Oil and Water are immiscible
  thus you can see layers in the
  mixture.
  IMMISCIBLE
• 2 or more liquids that do
  NOT mix into each other
   Gases can mix with
   liquids
• Carbonated drinks are
  homogeneous mixtures.
• They contain sugar, flavorings,
  and CO2 gas, dissolved in water.
  • When carbonated drinks are
    manufactured, the CO2 gas is
    mixed into the liquid under
    pressure and forms a solution.
Gases can mix
with liquids

    • Liquids not under pressure
      can also contain dissolved
      gases.
        • If you let a glass of ice water sit
          out over night, you may see
          bubbles on the sides of the glass
          the next morning. The bubbles are
          some of the air that was dissolved
          in the cold water.
2.1 Section Review
On a separate sheet of notebook
paper answer the following questions:

1: List the 2 types of pure substances

2: Complete the following:
     A heterogeneous mixture is to a homogeneous
     mixture as immiscible liquids are to _______.
3: Classify each as an element or mixture:
       Sulfur (S8); Carbon Monoxide(CO); Methane (CH4)

4: Give an example of a mixture and a pure substance.
 Solutions and
 Other Mixtures
 (Ch 6-1 and 6-2)
OBJECTIVES
 • Homogeneous vs. Heterogeneous
   mixtures
 • Compare and Contrast:
       solutions, colloids, suspensions
 • Identify ways to separate mixtures
CLASSIFYING MATTER

                      Elements
         Pure
         Substance
                      Compounds
MATTER
                     Homogeneous
         Mixtures


                     Heterogeneous
Solutions and
Homogenous mixtures

  SOLUTIONS & HOMOGENOUS
  MIXTURES are synonymous.

   Homogenous mixtures are mixed
   completely, all the way down to
   their most fundamental particles-
   atoms, molecules, or ions.
Solutions and
Other Mixtures
• Heterogeneous Mixtures
   • Ex: Fruit Salad
     − NOT the same throughout
     − Quantity of each fruit varies with each
       spoonful
Heterogeneous Mixture
SUSPENSION
• Have you ever forgotten to
  shake the OJ bottle before you
  poured a glass?
  • Probably tasted watery
    • Due to suspensions of orange pulp in
      OJ, which is mostly water
SUSPENSION
a mixture that
looks uniform
when stirred or
shaken that
separates into
different layers
when it is no
longer agitated
Suspension
    • SUSPENSIONS a mixture that looks
      uniform when stirred or shaken that
      separates into different layers when it is
      no longer agitated


• OJ:
  • If carton is not shaken, then
    the pulp goes to the bottom
    and the watery liquid sits on
    top.
Suspension

• Not all OJ has pulp
  • It can be separated out
  • Particles in suspensions are
    usually large enough they can be
    filtered out of mixture
      − (pulp stays behind)
Solution
Suspension
• All components are   Mixture of water
  evenly distributed   and nondissolved
• dissolved            materials
• (salt in water)      (flour in water)
  COLLOID

• Gelatin  heterogeneous mix
 • Gelatin is a colloid
 • Colloid a mixture of very tiny
  particles of pure substances that
  are dispersed in another
  substance but do not settle out
  of the substance
 Colloids

• Differences between suspensions
  and colloids:

   • Particles in colloids are much smaller
   • Because they are so small, they do NOT
     separate out or settle to the bottom in
     colloids
   • Particles stay dispersed throughout the
     mixture
Colloids

• EXAMPLES:
   • Egg white
   • Paint
   • Blood
   • Whipped cream (dispersing gas in a
     liquid)
   • Marshmallows (dispersed gas in a
     solid)
Heterogeneous
liquid-liquid mixtures
• Oil + vinegar  2 layers
  • They are immiscible
  • Oil floats on vinegar b/c less dense
• To separate mixture:
    • Cup with spout
    • Cooks use this to
      separate fat from
      meat juices; fat is
      less dense thus stays
      behind in the cup
 Some immiscible
 liquids can mix in
 EMULSIONS

EMULSION:
Any mixture of
immiscible liquids
in which the
liquids are spread
throughout one
another
Emulsions

• EXAMPLE:
   • Mayonnaise mixture of oil
     suspended in vinegar
     − They stay mixed (unlike that in salad
       dressing) because mayonnaise also
       contains egg yolk
     − Egg yolk coats the oil droplets keeping
       them from joining to form a separate layer
     − Thus, mayonnaise is an emulsion
         – (colloid where liquids normally do not
           mix are spread throughout each other)
Homogeneous Mixtures

• Not only look uniform, they
  ARE uniform
• Ex: Salt water
    • If you add salt to a glass of pure
      water and mix it, it will eventually
      look like pure water
    • Looks uniform because the
      components of the mixture are too
      small to be seen
Homogeneous Mixtures

• When salt and water mix, no
  chemical reaction takes place
   • Easy to separate the 2 substances by
     evaporating or boiling the water
   • Once boiled, only left with salt
Solutions are
Homogenous Mixtures

    • When you add aquarium salt
      to water and stir, the solid
      seems to disappear.
    • What is really happening??
Solutions are
Homogenous Mixtures

      • The solid DISSOLVES in
        water to form a solution
      • In this example, the
       aquarium salt is the
       solute, and the water is
       the solvent.
 Solute and Solvent…

• A SOLUTE is the
  substance that
  DISSOLVES in a
  solution.

• A SOLVENT is the
  substance that
  dissolves the solute to
  make a solution.
   SOLUTIONS
• When a solute completely
  dissolves in a solution, the
  dissolved particles are so
  small that you cannot see
  them

• Solutes and solvents can
  be in any state of matter.
SOLUTIONS

• Ex:
    • VINEGAR  A solution of Acetic
      Acid, a liquid, dissolved in water,
      another liquid

    • A tank of air used by a scuba
      diver can be thought of as a
      solution of oxygen and several
      other gases.
 Miscible Liquids 
 mix to make solutions


Water + Isopropanol  rubbing alcohol

   (both liquids)          solution

 Acetic Acid + Water      Vinegar
Miscible Liquids

• Since miscible liquids
  DO NOT separate into
  layers, they do not
  separate as easily as
  immiscible liquids do.

• One way to separate
  miscible liquids is by
 distillation
  Miscible Liquids
• Distillation is the easiest way
  to separate two miscible
  liquids

  • Distillation can be used when
    wanting to separate water and
    methanol
      − Boiling points of the 2 are significantly
        different
      − BP WATER = 100
      − BP Methanol = 67
 Distillation

1. heat entire mixture until
  it boils
2. Liquid with lower boiling
  point would vaporize first
        (methanol @ 67 deg)
3. Some water would
  vaporize, but most would
  stay behind
   Chromatography
• If 2 miscible liquids have
  similar boiling points it
  can be even harder to
  separate by distillation
• Chromatography can be
  used anytime it is too
  difficult to separate by
  distillation
Chromatography

the science which studies the
separation of molecules based on
differences in their structure and/or
composition.

Chromatographic separations can be carried out
using a variety of supports, including:
      immobilized silica on glass plates
                 (thin layer chromatography)
      volatile gases (gas chromatography)
      paper (paper chromatography)
      and liquids which may incorporate hydrophilic
      insoluble molecules (liquid chromatography).
DISSOLVING AND
SOLUBILITY
DISSOLVING AND
SOLUBILITY
Dissolving Rate

• Factors that affect dissolving
  rate of a solute in a solvent

• Can you think of any on your
  own???
SURFACE AREA

• Solutes with a larger
  surface area dissolve
  faster
   A substance in small pieces
   dissolves faster than the same
   substance in big pieces
    • EXAMPLE:
      − Loose sugar vs. Sugar cube
      − Chewable Vitamin C vs. pill swallowed
Shaking or Stirring
If you pour sugar in a glass and let it sit
without stirring, it will take longer for the
sugar to dissolve completely
 --sugar sitting at the bottom of the glass is surrounded by dissolved sugar
molecules – these molecules will slowly diffuse throughout the solution
Until they spread through the entire solution the dissolved sugar keeps the
water molecules from reaching the sugar crystals that haven’t dissolved yet.
Shaking or Stirring
If you pour sugar in a glass and let it sit
without stirring, it will take longer for the
sugar to dissolve completely

stirring or shaking the solution moves the dissolved sugar
away from the sugar crystals. Now more water
molecules can interact with the solid,
so the sugar crystals
 dissolve faster.
TEMPERATURE

• Sugar and other solutes
  dissolve faster in HOT
  water than in cold
  water.
 • Remember, that as a substance is
   heated, its particles move faster
 • As a result there are more
   collisions between particles and
   each collision transfers energy
  TEMPERATURE
• For gases, it is different…

  • Solubility is INVERSELY
    PROPORTIONAL to temperature for
    gases
    • The lower the temperature of the
      solvent, the higher the solubility
    • EX: Hot sodas will go flat!!
 PRESSURE
DOES NOT affect the
solubility of solids!!!

The solubility of a gas is
affected by pressure…
  • Solubility is DIRECTLY
    PROPORTIONAL to pressure for gases
     − The HIGHER the pressure, the
       HIGHER the solubility
     − Think SCUBA divers and their gas
       tanks!
NOT EVERY
SUBSTANCE WILL
DISSOLVE
• If a solute DISSOLVES in a
  solvent then it is said to be
  SOLUBLE
    • Example: Salt in Water
• If a solute DOES NOT DISSOLVE
  in a solvent then it is said to be
  INSOLUBLE
    • Example: Olive Oil in water
         – They form two separate layers
Water
• Most abundant compound in
  most living things!
WATER:
    A common Solvent

• 2/3 of the Earth’s surface is water
• Liquids we drink mostly water
• ¾ of body weight is water
• Many substances can dissolve in
  water therefore,
  WATER IS THE UNIVERAL SOLVENT!!!
WATER

• Water is the universal
  solvent

• The structure of water helps
  it dissolve charged particles

• Water is polar – uneven
  distribution of electrons
Hydrogen Bonding

• Polarity causes attraction
WATER = THE Universal Solvent

The figure below shows why NaCl easily
dissolves in water…
     • Sodium ions are attracted to the partially negative
       oxygen atom, and Chloride ions are attracted to the
       partially positive Hydrogen atoms
     • Interactions between the ions and water molecules pull
       the ions away from the solid
  Like Dissolves Like
Water can dissolve MANY
substances, but not all
   • EX: oil or gasoline doesn’t dissolve in water
 • Methanol is soluble in water because
   both liquids are polar
     − They have partially charged atoms that are
       attracted to one another
   • Gasoline: NOT SOLUBLE in water because its
     components are nonpolar
           Nonpolar = molecules do not have
            partial charges on opposite ends
CONCENTRATION

Solutions can have different concentrations
depending on how much solute and solvent
are present
CONCENTRATION

CONCENTRATION 
    THE QUANTITY OF SOLUTE
    DISSOLVED IN A GIVEN
    QUANTITY OF SOLUTION
CONCENTRATION




 If a small quantity of solute is dissolved in
 a large volume of solvent, the resulting
 solution is said to be dilute

 A concentrated solution has a large
 quantity of solute dissolved in the
 solvent.
Saturated Solutions

• Saturated Solution: contains the
  greatest quantity of solute that will
  dissolve in a given quantity of solvent

• SOLUBILITY: the greatest quantity of a
  solute that will dissolve in a given
  quantity of solvent to produce a
  saturated solution
SOLUBILITY
Solubility  the maximum amount
of a solute that can be dissolved in a
given solvent at a certain temperature
and pressure
Try thinking of it like “solute capacity”, like the seating of
a restaurant
          -solubility = seating capacity
          - solute = people
          - solvent = seats
    EVERY “restaurant” (or solvent) is different!!!
Saturated and
Unsaturated Solutions
Unsaturated Solution 
• a solution that is able to dissolve more
  solute


Saturated Solution 
• A solution that cannot dissolve any more
  solute at the given conditions
SUPERSaturated
 Solutions

    • Supersaturated Solution: a solution
      holding more dissolved solute than is
      specified by its solubility at a given
      temperature

    • Supersaturated solutions are unstable
      systems because the solute’s solubility
      is exceeded for a short time.
SUPERSaturated
 Solutions
                 Adding a single crystal of sodium
                 causes the excess sodium acetate to
                 quickly crystallize out of the
                 solution until the solution is
                 saturated at the cooler temperature
SUPERSaturated
 Solutions
• 2 ways to bring a
  supersaturated solution back to
  a saturated solution…

  1 heating up the solution to
   dissolve more solute
  2 adding more solvent to the
   solution in order to dissolve the
   solute

				
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