Section 3.3 Mixtures of Matter

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Section 3-3
Section 3.3 Mixtures of Matter

• Contrast mixtures and substances.

• Classify mixtures as homogeneous or
  heterogeneous.
• List and describe several techniques used to
  separate mixtures.

substance a form of matter that has a uniform
and unchanging composition also known as a pure
substance
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Section 3-3
Section 3.3 Mixtures of Matter (cont.)
mixture heterogeneous mixture homogeneous
mixture solution filtration
distillation crystallization sublimation chromatog
raphy
Most everyday matter occurs as mixturescombinatio
ns of two or more substances.
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Section 3-3
Mixtures

• A mixture is a physical combination of two or
  more pure substances in which each pure substance
  retains its individual chemical properties.

• A homogenous mixture is a mixture where the
  composition is constant throughout.

Homogeneous mixtures are also called
solutions. Examples
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C. Mixtures

• Solution
• homogeneous
• very small particles
• no Tyndall effect

• particles dont settle
• EX rubbing alcohol

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Section 3-3
Mixtures (cont.)
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Section 3-3
Mixtures (cont.)

• A heterogeneous mixture is a mixture where the
  individual substances remain distinct.
• mixture is not uniform in composition
• Examples

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C. Mixtures

• Colloid
• heterogeneous
• medium-sized particles
• Tyndall effect
• particles dont settle
• EX milk

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C. Mixtures

• Suspension
• heterogeneous
• large particles
• Tyndall effect
• particles settle
• EX fresh-squeezed lemonade

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C. Mixtures

• colloid
• suspension
• colloid
• solution
• suspension

• Examples
• mayonnaise
• muddy water
• fog
• saltwater
• Italian salad dressing

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Section 3-3
Separating Mixtures

• Filtration is a technique that uses a porous
  barrier to separate a solid from a liquid in a
  heterogeneous mixture.

• Distillation is a separation technique for
  homogeneous mixtures that is based on the
  differences in boiling points of substances.
• Crystallization is a separation technique for
  homogenous mixtures that results in the formation
  of pure solid particles from a solution
  containing the dissolved substance.

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Section 3-3
Separating Mixtures (cont.)

• Sublimation is the process of a solid changing
  directly to a gas, which can be used to separate
  mixtures of solids when one sublimates and the
  other does not.

• Chromatography is a technique that separates the
  components of a mixture on the basis of tendency
  of each to travel across the surface of another
  material.

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Section 3-3
Section 3.3 Assessment
Which is NOT a technique for separating a
homogenous mixture? A. crystallization
B. distillation C. filtration D. chromatography

1. A
2. B
3. C
4. D

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Section 3-3
Section 3.3 Assessment
Which of the following is a heterogeneous
mixture? A. seawater B. silver mercury
amalgam C. atmosphere D. salad dressing

1. A
2. B
3. C
4. D

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Section 3-4
Section 3.4 Elements and Compounds

• Distinguish between elements and compounds.

• Describe the organization of elements in the
  periodic table.
• Explain how all compounds obey the laws of
  definite and multiple proportions.

proportion the relation of one part to another
or to the whole with respect to quantity
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Section 3-4
Section 3.4 Elements and Compounds (cont.)
element periodic table compound
law of definite proportions percent by mass law
of multiple proportions
A compound is a combination of two or more
elements.
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Section 3-4
Elements

• An element is a pure substance that cannot be
  separated into simpler substances by physical or
  chemical means.

• 92 elements occur naturally on Earth.
• Each element has a unique name and a one, two, or
  three-letter symbol.
• The periodic table organizes the elements into a
  grid of horizontal rows called periods and
  vertical columns called groups.

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Section 3-4
Compounds

• A compound is a made up of two or more elements
  combined chemically.

• Most of the matter in the universe exists as
  compounds.
• Table salt, NaCl, and water, H2O, are compounds.

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Section 3-4
Compounds (cont.)

• Elements can never be separated.

• Compounds can be broken into components by
  chemical means.

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A. Matter Flowchart
MATTER
no
Can it be physically separated?
yes
Compound
Element
Homogeneous Mixture (solution)
Heterogeneous Mixture
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Section 3-4
Law of Definite Proportions

• The law of definite proportions states that a
  compound is always composed of the same elements
  in the same proportion by mass, no matter how
  large or small the sample.

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Section 3-4
Law of Definite Proportions (cont.)

• The relative amounts are expressed as percent by
  mass, the ratio of the mass of each element to
  the total mass of the compound expressed as a
  percentage.

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Section 3-4
Law of Definite Proportions (cont.)

• This table demonstrates that the percentages of
  elements in sucrose remain the same despite
  differences in sample amount.

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Section 3-4
Law of Multiple Proportions

• The law of multiple proportions states that when
  different compounds are formed by a combination
  of the same elements, different masses of one
  element combine with the same relative mass of
  the other element in whole number ratios.

• H2O2 and H2O
• Copper(I) chloride and copper(II) chloride

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Section 3-4
Law of Multiple Proportions (cont.)
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Section 3-4
Section 3.4 Assessment
What is a period on the periodic table of the
elements? A. a vertical columns B. even
numbered elements only C. horizontal rows
D. the last vertical column only

1. A
2. B
3. C
4. D

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Section 3-4
Section 3.4 Assessment
An element is a substance that cannot be
A. divided into simpler substances. B. combined
to form a mixture. C. combined to form an
element. D. different phases.

1. A
2. B
3. C
4. D