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					            Matter
Properties and Composition




            http://z.about.com/d/chemistry/1/0/x/c/transitionmetalsolns.jpg



 CHM 1010          PGCC                        Barbara A. Gage
                  Properties
• Physical Property - any property that
  can be observed without transforming
  the substance into another substance
          mass, color, freezing point
• Chemical Property - any property that
  cannot be studied without transforming
  the substance into a different
  substance
          iron rusts, paper burns
       CHM 1010      PGCC   Barbara A. Gage
                  Changes
• Physical Change - change that does not
  transform the substance into another
  substance
  melting, subliming, dissolving




       CHM 1010    PGCC     Barbara A. Gage
                   Changes
• Chemical Change - change that
  transforms the substance into another
  substance
     burning, oxidation of metal

• http://jchemed.chem.wisc.edu/JCESoft
  /CCA/pirelli/pages/cca1NaIHgCl2.html


        CHM 1010     PGCC    Barbara A. Gage
      Chemical Change




                  From Silberberg, Principles of Chemistry, 2007

CHM 1010   PGCC        Barbara A. Gage
Figure 1.1   The distinction between physical and chemical change.
              (Silberberg)




     A Physical change                     B Chemical change


             CHM 1010          PGCC           Barbara A. Gage
 Sample Problem 1.1        Distinguishing Between Physical and
 (Silberberg)              Chemical Change

PROBLEM: Decide whether each of the following process is primarily a
         physical or a chemical change, and explain briefly:
  (a) Frost forms as the temperature drops on a humid winter night.
  (b) A cornstalk grows from a seed that is watered and fertilized.
  (c) Dynamite explodes to form a mixture of gases.
  (d) Perspiration evaporates when you relax after jogging.
  (e) A silver fork tarnishes slowly in air.

PLAN:     “Does the substance change composition or just change
       form?”
SOLUTION:
   (a) physical change      (b) chemical change        (c) chemical change

            (d) physical change            (e) chemical change



              CHM 1010              PGCC               Barbara A. Gage
CHM 1010   PGCC   Barbara A. Gage
          Types of Matter
• Element - the simplest type of
  substance with unique physical and
  chemical properties. It cannot be
  broken down into any simpler substances
  by physical or chemical means.
• Compound - a substance composed of
  two or more elements which are
  chemically combined.

       CHM 1010   PGCC     Barbara A. Gage
Figure 2.19              The distinction between mixtures and compounds.
Silberberg




                                                                    S



                                                                    Fe

 Physically mixed therefore can be      Allowed to react chemically
 separated by physical means; in        therefore cannot be separated by
 this case by a magnet.                 physical means.


              CHM 1010           PGCC             Barbara A. Gage
CHM 1010   PGCC   Barbara A. Gage
         Types of Matter
• Atom – smallest unit of an element with
  all the characteristics of the element




        CHM 1010   PGCC      Barbara A. Gage
           Types of Matter
• Molecule - a structure that consists of
  two or more atoms that are chemically
  bound together and thus behaves as an
  independent unit.
                  Figure 2.1
                  Silberberg




       CHM 1010          PGCC   Barbara A. Gage
                     The boxes here contain
                     submicroscopic views of
                     particles. Indicate
                     which box(es) contain
                     the stated item(s) and
                     why.

                     a.only elements
                     b.only one compound
                     c.mixture of compounds
                     d.molecules


                      a.   B, C, E
                      b.   A (plus an element), D
                      c.   F
                      d.   All but E




CHM 1010   PGCC   Barbara A. Gage
 Element Names and Symbols
• Number of elements – 117 (#117 has not
  been identified but 118 has)




      CHM 1010   PGCC    Barbara A. Gage
    Element Names and Symbols
• Each element has a name and 1, 2 or 3
  letter abbreviation called a symbol. The
  first letter in a symbol MUST be capital
  and the other(s) lowercase.

•   hydrogen       H      helium    He
•   carbon         C      cobalt    Co
•   sodium         Na     potassium K
•   lead           Pb     mercury Hg
                                               Image from WebElements

        CHM 1010   PGCC      Barbara A. Gage
 Element Names and Symbols
• You must know the names and symbols
  of the first 38 elements on the periodic
  table along with Ag, Cd, Sn, I, Ba, Hg,
  Pb.
• Spelling counts!
• Make flashcards to help
  learn them.

                         www.chem.purdue.edu/gchelp/liquids/bromine.gif

       CHM 1010   PGCC        Barbara A. Gage
        Chemical Formulas
• Some elements appear in nature bonded
  to each other. These are referred to
  as diatomic or polyatomic molecules.
  H2, O2, N2, F2, Cl2, Br2, I2 (must know)
   C60, S8, P4
• The 2 in O2 is termed a subscript and
  refers to the element immediately in
  front of it.

        CHM 1010    PGCC     Barbara A. Gage
         Chemical Formulas
• CO2 contains 1 atom of carbon and two
  atoms of oxygen all chemically linked.
• H2SO4 contains 2 hydrogen, 1 sulfur,
  and 4 oxygen atoms.
• (NH4)2C2O4 - A subscript outside
  parentheses applies to everything within
  the parentheses; 2 N, 8 H, 2 C, 4 O


       CHM 1010   PGCC     Barbara A. Gage
CHM 1010   PGCC   Barbara A. Gage

				
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