St Catharine College Chemistry 103 Experiment 1 Experiment 1 Elements Compounds Physical and Chemical Properties by gvl14091

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									St. Catharine College               Chemistry 103                          Experiment 1

                 Experiment 1
    Elements,Compounds, Physical and Chemical
                   Properties

Introduction

The most important skill to any scientist is that of observation. Only when observation
skills are sharp and the observations made are comprehensive and detailed can a scientist
develop good hypotheses and design relevant experiments to test them. You will practice
your observation skills in this experiment by recording descriptions of a variety of
elements and compounds. A description of a substance might include properties such as
color, odor, texture, size of particles, crystalline structure and state of matter. All of these
characteristics are physical properties.          Other physical properties are electrical
conductivity, density, heat capacity, solubility, hardness, melting and boiling
temperatures. Many of the physical properties of substances can be found in reference
books like the Merck Index or the CRC Handbook of Chemistry and Physics. There are
only slightly more than one hundred elements. There are tens of thousands of
compounds. One of the key activities of this lab is to compare and contrast the physical
properties of elements and the compounds containing those elements.

Contrasting with physical properties are the chemical properties of matter. A chemical
property is what happens to a substance when it comes in contact with another substance.
The rusting of iron in the presence of the oxygen in air is a common chemical property
with which we are all familiar. Chemical properties can only be observed by changing
the substance into a difference substance. For example, the only way to observe whether
a substance is flammable is to burn it and in making that observation we convert the
substance into other substances. In this lab, you will observe whether several elements
react with water and hydrochloric acid.


Today we will also introduce you to the distinction between metals and non-metals. It is
easy to determine whether an element is a metal or a non-metal by consulting the periodic
table. The elements boron, silicon, germanium, arsenic, antimony, tellurium, polonium
and astatine are the semi-metals or metalloids. On the periodic table, the elements that lie
to the right or above the metalloids are non-metals and the elements that lie to the left or
below the metalloids are metals. Hydrogen is the exception; it is a non-metal even
though it is in the extreme left hand side of the periodic table. It is important that we can
identify elements as metal or non-metals because it determines the type of compound the
element forms and how we name those compounds. This will be very important as we
continue our study of chemistry.




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St. Catharine College            Chemistry 103                      Experiment 1

Prelab:

1. Define the following terms.

          a. element ____________________________________________________

____________________________________________________________________

____________________________________________________________________

          b. compound ____________________________________________________

____________________________________________________________________

____________________________________________________________________

          c. substance ____________________________________________________

____________________________________________________________________

____________________________________________________________________

          d. chemical property_____________________________________________

____________________________________________________________________

____________________________________________________________________

          e. physical property _____________________________________________

____________________________________________________________________

____________________________________________________________________


2. Based upon your everyday observations, what are some of the physical properties you
associate with metals?




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St. Catharine College             Chemistry 103                      Experiment 1

Elements

1.    Find the symbol on the periodic table for each element below and record it in the
box below the element name. Circle whether the element is a metal or a non-metal.
2. Record your observations of the physical properties of the elements.

  Element                         Observations
  Oxygen                          Colorless gas
  symbol ____O______
  metal      non-metal
   sulfur
  symbol __________
  metal      non-metal
  carbon
  symbol __________
  metal      non-metal
  aluminum
  symbol __________
  metal      non-metal
  magnesium
  symbol __________
  metal      non-metal
  sodium*
  symbol __________
  metal      non-metal
  iodine
  symbol __________
  metal      non-metal
  iron
  symbol __________
  metal      non-metal
  zinc
  symbol __________
  metal      non-metal
  copper
  symbol __________
  metal      non-metal
  bromine
  symbol __________
  metal      non-metal




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St. Catharine College           Chemistry 103                      Experiment 1

Compounds

1.     Write the atomic symbols of the two elements that make up each compound in the
space below the compound name.
2.     Record the physical characteristics of the compounds provided.


Substance                     Observations
Carbon dioxide                Colorless gas

elements: C and O

zinc oxide

elements: _____________

Iron (II) sulfide

elements: _____________

sodium bromide

elements: _____________

sodium iodide

elements: _____________

sodium sulfide

elements: _____________

iron (II) oxide

elements: _____________

copper (II) bromide

elements: _____________



elements: _____________




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St. Catharine College             Chemistry 103                        Experiment 1

Chemical Properties

1.     Place a small particle of each of the following in a test tube. Add water. Record
your observations especially noting whether there are indications that a chemical reaction
occurred. (Note: The instructor will do the sodium as a demonstration. Handling of
sodium can be dangerous.)

       a. sodium _______________________________________________

       ________________________________________________________

       b. zinc _________________________________________________

       ________________________________________________________

       c. magnesium_____________________________________________

       ________________________________________________________

       d. copper _______________________________________________

       ________________________________________________________


2.      Place a small particle of each of the following in a test tube. Add hydrochloric
acid. Record your observations especially noting whether there are indications that a
chemical reaction occurred. (Safety: Be sure you are wearing eye protection when
using hydrochloric acid. Immediately flush eyes or skin if you come in contact with
the acid.)

       a. zinc _________________________________________________

       ________________________________________________________

       b. magnesium_____________________________________________

       ________________________________________________________

       c. copper _______________________________________________

       ________________________________________________________




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St. Catharine College               Chemistry 103                        Experiment 1

Questions

1. Based upon the physical properties of a substance, is it possible to tell whether it is an
element or a compound? Explain your answer using examples from this lab or everyday
observations.




2. Can you predict the physical properties of a compound based upon the physical
properties of the elements that make up the compound? Explain your answer using
examples from this lab.




3. If you look at the nutritional information of many foods you will find sodium listed.
Do you think this sodium is in the food as the element or as a compound? Explain your
answer.




4. Do you think it was easy for early chemists to determine whether the substances they
encountered were elements or compounds? Explain your answer.




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