Chapter 4 Elements_ Compounds and Mixtures by yurtgc548

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									           Chapter 4
 Elements, Compounds and Mixtures




         THE BIG IDEA…
Matter can be classified into elements,
      compounds and mixtures
           Section 1
           Elements
• In this section you will learn how
  to explain the characteristics of
  elements and gives examples
  of these characteristics. You will
  also learn how to identify and
  classify elements as metals,
  non-metals and metalloids
  based on their properties.
States of Matter – 20 minutes
              Bellringer
• Refer to Figure 4 in your book (page 93)
  for help answering the following
  questions:

• What do gold, iron, and aluminum have
  in common?

• What do oxygen, neon, and sulfur have
  in common?

• How is silicon different from aluminum or
  oxygen?
          Objectives
• Describe pure substances.

• Describe the characteristics of
  elements, and give examples.

• Explain how elements can be
  identified.

• Classify elements according to
  their properties
Vocabulary
•   Element
•   Pure substance
•   Metal
•   Non-metal
•   Metalloid


        Use your class hand out to draw a
    representation of the word after you have
           defined it in your notebook.
            Elements
       The purest substance
• An element is a pure substance that
  cannot be separated into simpler
  substances by physical or chemical
  means.
http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75006.htm



• A substance in which there is only one
  type of particle is a pure substance.

• Elements are made of particles called
  atoms.
   Identifying Elements by Their
             Properties
• Elements are identified by using
  their physical properties and
  their chemical properties.

• An element may share a
  property with another element

• properties can help you tell the
  elements apart.
http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75017.htm
      Classifying Elements
       by Their Properties

Three major categories are:
• Metals are shiny, and they conduct
  heat energy and electric current.

• Nonmetals conduct heat and
  electricity poorly.

• Metalloids have properties of both
  metals and nonmetals.
Section ONE:
 homework

             Metals




Non Metals            Metalloids
         Section 2
        Compounds
• This section describes the
  properties of compounds and
  explains the differences
  between compounds and
  elements. You will also learn
  about the properties and
  importance of common
  compounds
Elements and Compunds – 18 minutes
          Bellringer
• The word compound refers to
  something that consists of two
  or more parts. How might you
  make a compound using
  elements? What are some
  compounds that you know?

• Write your answer in your
  science journal.
         Objectives
•Explain how elements make up
 compounds.

•Describe the properties of compounds.

•Explain how a compound can be
 broken down into its elements.

•Give examples of common
 compounds.
   Compounds: Made of
       Elements
• A compound is a pure substance
  composed of two or more elements
  that are chemically combined.
http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75007.htm

• Elements combine by reacting with
  one another.

• A particle of a compound is a called
  a molecule.

• Elements join in a specific ratio
  according to their masses to form a
  compound.
       Breaking Down
        Compounds
• Compounds can be broken down
  into their elements or into simpler
  compounds by chemical changes.

• Energy is needed for a chemical
  change to happen.

• Two ways to add energy are to…
     • apply heat
     • apply an electric current.
       Section Three:
         Mixtures
• This section explains the
  properties of mixtures. You will
  learn how mixtures can be
  separated. The concepts of
  solutes, concentration, and
  solvents are covered. You will
  be able to compare solutions,
  suspensions and colloids.
Mixtures and Solutions 18 minutes
          Bellringer
• When you add sugar to coffee,
  tea, iced tea, or lemonade, the
  sugar disappears. What do you
  think happens to the sugar?

• Write your answer in your
  science journal.
             Objectives
• Describe three properties of mixtures.

• Describe four methods of separating the parts
  of a mixture.

• Analyze a solution in terms of its solute and
  solvent.

• Explain how concentration affects a solution.

• Describe the particles in a suspension.

• Explain how a colloid differs from a solution
  and a suspension.
  Properties of Mixtures
• A mixture is a combination of two or
  more substances that are not
  chemically combined.

• No chemical changes happen when a
  mixture is made.
  • each substance has the same
    chemical makeup it had before the
    mixture was formed.
  • Mixtures can be separated by using
    physical changes.
  • Physical changes do not change
    the identities of the substances.
  Properties of Mixtures,
       continued
• The components of a mixture do not
  need to be mixed in a definite ratio.



• Example
  • granite is a mixture of three minerals.
    Different ratios of the minerals give
    granite different colors, but the mixture
    is always called granite.
                      Solutions
• A solution is a mixture that appears to
  be a single substance. The process in
  which particles of substances separate
  and spread evenly throughout a
  mixture is known as dissolving.

• In a solution…
  • the solute is the substance that is
    dissolved.
  • The solvent is the substance in which
    the solute is dissolved.
•   http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75243.htm
      Solutions, continued
Examples of Solutions…




Solutions may also be solids, such as steel.
http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75243.htm

 Alloys (ancient India’s metallurgy) are solid
solutions of metals or nonmetals dissolved
in metals.
   Solutions, continued

• The particles in solutions are so
  small that they never settle out.

• They also cannot be removed
  by filtering.

• Light can pass through them
          Concentrations of
             Solutions
• A measure of the amount of solute
  dissolved in a solvent is concentration.

• Solutions can be described as being
  concentrated or dilute.
http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75261.htm

• But these two terms do not tell you the
  amount of solute that is dissolved.

• Solubility is the ability of a solute to
  dissolve in a solvent at a certain
  temperature.
 Concentrations of Solutions,
        continued
• Gases become less soluble in
  liquids as the temperature is
  raised.

• Three ways to make a solute
  dissolve faster are…
  • mixing the solution
  • heating the solution
  • crushing the solute into smaller
    particles.
   http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75251.htm
                 Suspensions
• A suspension is a mixture in which
  particles of a material are dispersed
  throughout a liquid or a gas but are
  large enough that they settle out.
http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75485.htm

• The particles in a suspension are large
  enough to scatter or block light.

• A suspension can be separated by
  passing it through a filter
                        Colloids
• A colloid is a mixture in which the
  particles are dispersed throughout but
  are not heavy enough to settle out.

http://my.hrw.com/sh2/sh07_10/student/flash/visual_concepts/75484.htm


• Particles in a colloid are large
 enough to scatter light.

• A colloid cannot be separated by
  passing it through a filter.
       Homework
• Concept Map

								
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