TAKS Review Objective 4'2

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TAKS Review Objective 4.2

• Matter and Change
• Mixtures and Solubility

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Decide if the substance is Element, Compound ,
or Mixture?
1. Water
1. Compound
2. Compound
2. Table Salt
3. Element
3. Oxygen
4. Mixture
4. Dirt
5. Mixture/Solution
5. Air
Click Mouse button to see answers!
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6.
A. B. C. D.
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7. All of these can affect the rate at which a
solid dissolves in water except

• A decreasing air pressure
• B stirring the water
• C increasing the temperature of the water
• D using larger crystals of the solid

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• 8. At which temperature do KBr and KNO3 have
  the same solubility?
• A 27C
• B 48C
• C 65C
• D 80C

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Check the rest of your answers to see if you need
to do this tutorial . . .

• A
• A
• B
• If you had all 8 questions correct, go to the end
  and take the quiz. . .

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Matter is divided into 3 types

• Elements
• Compounds
• Mixtures

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The 3 types can be further separated in two
categories

• Mixtures are not pure substances. Each part of a
  mixture keeps its own properties, and can be
  separated out by a physical change.

• Pure Substances
• Elements are the simplest pure substances

• Compounds which are formed when two or more
  elements share electrons or become ions that
  attract other elements.

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Lets try it again!
1. Copper
1. Element
2. Solution/Mixture
2. Soda
3. Solution/Mixture
3. Steel
4. Mixture
4. Rain
5. Mixture
5. Ice-cream
Click Mouse button to see answers!
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Law of Conservation of Matter

• Matter can not be created or destroyed.
• The total mass of the substances before they are
  mixed is equal to the total mass as a mixture.

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Changes in Matter Physical, Chemical or
Nuclear?

• Physical changes do not change the substance.
  The state of the matter may change, but it keeps
  its own properties.
• Cutting a piece of wood does not change the wood,
  it is simply smaller.

• Chemical changes are also called chemical
  reactions.
• When a different substance is produced than what
  was present at the start, a chemical change has
  occurred.

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Nuclear Changes Fission and Fusion

• Fusion occurs when the nucleus of one atom is
  joined by the nucleus of another.
• This is the reaction that occurs on the sun and
  stars.
• It produces extreme energy release.

• Fission occurs when the nucleus of an atom ejects
  particles and energy when hit by a subatomic
  particle such as a neutron.
• This also causes a release of extreme energy and
  is the basis of atomic energy plants and bombs.

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There are two types of mixtures

• Heterogeneous- mixture is not the same from place
  to place.
• Chocolate chip cookie, gravel, soil.

• Homogeneous- same composition throughout.
• Kool-aid, air, brass.

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P r o p e r t i e s o f M i x t u r e s

• E a c h s u b s t a n c e r e t a i n s
  i t s o w n p r o p e r t i e s .
• S u b s t a n c e s c a n b e
  p r e s e n t i n a n y a m o u n t .
  
• S u b s t a n c e s c a n b e
  s e p a r a t e d b y s i m p l e
  p h y s i c a l m e a n s.

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Separating Mixtures Physical Changes

• Separation of mixtures could be
• Magnetic removal (if there is Fe, Ni, Co)
• Filtration (if there are large particles)
• Hand sorting particles
• Decanting (pouring off the less dense liquid)

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Another technique for separating mixtures

• Evaporation changing from a liquid to vapor
  state leaves behind the other component.

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• Distillation
• Process used to remove vapor from liquid by
  heating
• Great for separating two or more liquids which
  have different boiling points.

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So, what is a suspension or colloid?

• Colloids have small particles that are not
  visible by just looking. An example would be
  coffee.
• However, they show the Tyndall Effect (see the
  laser light line).
• They can not be separated by filtering.

• Suspensions have larger particles, often visible
  in size.
• The particles can be filtered out.
• It scatters light No Tyndall Effect.
• If left undisturbed, the particles will settle
  to the bottom.

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Solutions 2 parts

• S o l v e n t - t h e m o s t
  a b u n d a n t s u b s t a n c e
  i n t h e s o l u t i o n .
  
• S o l u t e - t h e l e a s t
  a b u n d a n t s u b s t a n c e
  i n t h e s o l u t i o
  n .
• Homogeneous You can not see any particles of
  either part!

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The three methods to increase the rate of
solution for a solid are?

• Heat it!
• Crush it!
• Stir it!

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Gases also dissolve in

• Other gases, such as the solution called air.
• Liquids, such as soda. More gas dissolves at
  lower temperatures and higher pressures.

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Remember question 6?
6.
Crush it, remember! A powder has more surface
area so it will go into solution faster, and
provide relief faster. Answer F
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7. All of these can affect the rate at which a
solid dissolves in water except
Except --

• A decreasing air pressure
• B stirring the water
• C increasing the temperature of the water
• D using larger crystals of the solid

What are the 3 ways it is increased? Eliminate
them since it says EXCEPT!
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Solubility Factors What will dissolve?

• Solubility Rules
• 1. All sodium, potassium, and ammonium salts are
  soluble.
• 2. All silver, lead, and mercury salts are
  insoluble.
• 3. All carbonates, sulfides, and hydroxides are
  insoluble.
• 4. All nitrates and sulfates are soluble except
  calcium sulfate and barium sulfate.

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Lets apply the rules to this example.

• 4. Which of the following salts has the greatest
  solubility in water at 25C?
• A CaCO3
• B FeS
• C HgCl2
• D KClO4

This is a carbonate Insoluble!
This is a sulfide Insoluble!
This is mercury Insoluble!
This is a salt called Potassium chlorate.
Potassium salts are soluble. Answer?
D
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Solubility Factors What will really dissolve?
Like dissolves like.
Polar substances like salts dissolve in polar
substances like water. Water is called the
Universal Solvent because it is polar and
dissolves many salts Nonpolar substances like
proteins dissolve in nonpolar substances like
acetone or methyl alcohol.
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How much solute will dissolve?

• A solubility curve shows the amount of each
  solute that will dissolve in 100g H20 at each
  temperature.
• Saturated is on the line.
• Unsaturated is below the line.
• Supersaturated is above the line.

Grams solute/100 g H2O
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• At which temperature do KBr and KNO3 have the
  same solubility?
• A 27C
• B 48C
• C 65C
• D 80C

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Try this one!
5. According to the graph, about how much
hemoglobin would be saturated at an O2 pressure
of 7.3 kPa? A 32 B 67 C 89 D 92
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Concentrated or Dilute?

• A concentrated solution has as little solvent as
  possible.
• A dilute solution has added solvent.
• After adding more solvent, there is still the
  same mass of solute that you started with.

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pH is a measure of the Strength of Acids Bases

• Acids have 0-6.99 pH
• Bases have 7.01-14 pH
• Remember because A begins the alphabet and zero
  begins numbers
• Litmus turns red in acids and blue in bases
• Phenothalein turns pink in a base and stays clear
  in acids.

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Properties of Acids and Bases

• Acids form H ions in a water solution.
• React with metals to form metal salts and release
  hydrogen.
• Turn litmus red.
• Taste sour.
• Have a pH between 0-6.99

• Bases form OH- ions in a water solution.
• They dissolve fats and oils.
• Turn litmus blue.
• Taste very bitter and feel slippery.
• Have a pH over 7 and up to 14.

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Chemical Reactivity

• Metals increase in reactivity left and down.
• Nonmetals become more reactive up and to the
  right.
• Most reactive metal is?
• Most reactive nonmetal is?

Fr
F
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For the next 7 slides, write your answer on your
own paper under the title Obj. 4.2.
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• 1. Which of these if an example of a
  homogeneous mixture?
• Salt and pepper
• Salad with tomatoes and carrots
• Saltwater solution
• Fertilizer

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• 2. Which of the following describes a
  homogeneous mixture?
• A. An element
• B. Two or more substances that are evenly spread
  out in another material
• C. Individual molecules, unevenly spread out
• D. One substance turned into another.

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• 3. Which of the following is a physical change?
• Burning
• Digesting
• Exploding
• Melting

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• 4. Which of the following makes water be a
  universal solvent?
• Its highly soluble.
• Its neutral.
• Its nonpolar.
• Its polar.

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• 5. Four different solutions have the following
  pH values. Which solution has a higher
  concentration of hydroxide ions?
• pH 2
• pH 5
• pH 7
• pH 10

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• 6. To increase the solubility of a gas in water,
  you could
• A. Agitate the surface of the water
• B. Increase the concentration of the gas
• C. Increase the pressure of the gas on the
  surface of the water
• D. Increase the temperature of the solution

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Solubility Curve of Potassium Nitrate
Concentration (g/100 g H2O)
Temperature (oC)

• 7. A saturated solution of potassium
  nitrate is prepared in 100 grams of water heated
  to 60oC. How many grams will have settled out of
  the solution once it cools to 24oC?
• 30 g
• 65 g
• 95 g
• 145 g

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Check your answers, and turn them in. . .

• 1. C 2. B 3. D 4. D 5. D 6. C
  7. B
• Be sure your name and your teachers name are on
  the paper. Pick up your bonus buck on the way
  out!!

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• Only 1 more objective to go! Next is 5.1. . .