Ch' 7 Solutions

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Ch. 7 Solutions
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• Solutions and Other Mixtures
• Any sample of matter is either a pure substance
  or a mixture of pure substances
• A. Heterogeneous Mixtures
• 1. hetero different
• 2. A heterogeneous mixture is made of
  different amounts of different substances

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3. examples fruit salad, dirt from a
garden, mixed nuts 4. each spoonful is
different B. Suspensions 1. Def a
mixture in which particles are more or less
evenly dispersed throughout the gas or liquid

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2. orange juicethe pulp will settle to the
bottom if the carton sits for a while 3. in
any suspension, the particles will settle over
time 4. the particles in a suspension
can be filtered out
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If you can filter particles out of a solution,
its a suspension. 5. liquid mixtures can also
separate a. Oil and water b. Salad
dressing c. They are called immisible they
dont mix
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d. you can pour the less dense liquid off
the heavier one C. Colloids 1. Another type
of heterogeneous mixture 2. particles in
colloids are much smaller than they are in
suspensions 3. Cant be filtered
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4. The particles in a colloid can scatter
light ex. Fog is an example of a colloid.
The water particles are dissolved in the air
making it difficult to see. If you put your
brights on, it sometimes makes it more
difficult to see 5. other colloid ex. are
Jello, whipped cream, egg whites
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6. Immiscible liquids can form
colloids a. mayonnaise is a colloid of
very small fat droplets suspended in an
acidsometimes vinegar, sometimes lemon
juicedepends on the recipe. b. But
without egg yolk or mustard, the colloid wont
stay together
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c. The egg yolk coats the oil droplets and
stops them from forming together to form a
separate layer d. This is called an emulsion
a mixture of two immiscible liquids in which
one stays dispersed in the other e. The
particles are so small that it appears uniform,
but its not
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D. Homogeneous Mixtures 1. Not only do
they look uniform, they are uniform 2. salt
water is an example of a homogeneous mixture 3.
the solution will look uniform even under a
microscope 4. when salt and water are mixed,
no chemical reaction occurs
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5. So, these particles can be separated
even though the sodium and chlorine from the
salt are surrounded by water 6. How could you
separate the salt from the water in a salt water
solution? 7. Homogeneous mixtures are
solutions a. If you mix salt and water,
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• the salt dissolves in the water
• b. The salt is a solute and the water is the
  solvent. When a solute dissolves in a solvent,
  the dissolved particles are so small that you
  cant see them
• Miscible liquids form solutions
• 2 or more liquids that form a single layer when
  mixed are

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misible b. Skin lotion is an example of a
homogeneous mixture of miscible liquids c. A
liquid solution can not be separated easily.
They have to be distilled, and this only works if
the solutions have two different boiling points
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• Other states of matter can form solutions
• 1. Gas in a liquid? Soda
• 2. Liquid in a gas? Fog
• 3. Gas in a gas? Air
• 4. Solid in a liquid? Kool-Aid
• 5. Liquid in a solid? Cavity filling
• 6. Solid in a Solid? Whoa

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• Thats an alloy! 1. If a solid is dissolve in
  another solid, you produce a new solid called an
  alloy.
• The two solids must be melted to be dissolved in
  each other, but when the mixture cools, youve
  got a new metal with different properties than
  the first two

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• Alloy examples
• a. brass combines copper and zinc
• b. Bronze combines copper and tin

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• Solubility and Concentration
• A. Solubility in Water
• 1. solubility the maximum amount that can be
  dissolved in a solvent
• 2. no matter how much you stir, you cant get
  oil to dissolve in water
• a. It is insoluble in water

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B. Different substances have different
solubilities 1. depends on the strength of the
forces acting between the water molecules and the
molecules of the solute and the forces holding
the solute together 2. If something is very
soluble in water, the force holding it together
is less than the force between the water
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and that molecule. 3. How much can
dissolve? a. concentration refers to how much
of a solute is present in a solution more
solute higher concentration b. If there is
very little of a solute in a solution it is
dilute
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4. Unsaturated solutions a. contains less
than the maximum amount that can be dissolved in
a solution b. A solution is unsaturated as
long as it can dissolve more solute 5.
Saturated solutions a. Can dissolve no more
solute
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b. if you add more solute, no matter how
much you stir, it doesnt dissolve c. It is
in equilibrium 6. The supersaturated
solution! a. If you heat a saturated
solution, you can add more soluteand it
stays in solution! It is supersaturated!
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7. Temperature and Pressure a. Gases
can also dissolve b. Soda is a solution of
gas and liquid c. At a cooler temp, the gas
will remain dissolved longer d. Pressure
can also affect solubilitywhen you open the soda
bottle, you release the pressure and
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the gas escapes! C. Concentration of
Solutions 1. Mass percent a. Grams of
solute per 100 g of solution 2. To make a
5 solution of salt, youd dissolve 5 grams of
salt to 95 grams of water