CHEM 1405

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					Introduction to Chemistry
      CHEM 1405
        Section P02
       Dr. John Stankus
        Week 1 presentations

             CHEM 1405         1
• Dr. John Stankus
  – Office Hours Thursday 1-2 p.m. in Math Lab
     • Additional office hours by appointment
  – Contact
     • Email
     • Voice mail: 972-578-5550 x 8155

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• Lecture
  – Exams - 5 equal weighted tests (100 pts each)
     •   Exam 1
     •   Exam 2
     •   Exam 3
     •   Exam 4
     •   Comprehensive final -
  – Quizzes (10 pts each)
• Recitation Grade
  – Homework
  – Attendance/Participation
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              Course Grade
• Lecture Grade 70% of final course grade
• Recitation Grade 10% of final course grade
• Laboratory Grade 20% of final course grade

• Please tell me the laboratory section you are
  registered in if you are not in my laboratory
  section (meets immediately before this)

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    Introduction to Chemistry, Classification
           of Matter, Measurements
•    1. How do scientists obtain new scientific knowledge? Do views or concepts in
     science change?
•    2. What is chemistry?
•    3. How does mass differ from weight?
•    4. How do physical properties of matter differ from chemical properties?
•    5. What is the difference between a mixture and a compound?
•    6. What is energy? What is potential energy? What is kinetic energy?

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       How science works
    The Scientific method (1.3)
                     Find Patterns, and

                       Formulate and
                      Test Hypothesis


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 Observations and Experiments

        • Identify all possible variables
        • Control the experimental conditions
        • Methodically change one of the variables
        • Observe the results
            • Record the experimental conditions
            • Record the variables values
            • Record all results seen

    A variable is a data item that changes over the course of an experiment

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Find Patterns, and

  Formulate and
 Test Hypothesis
                • Examine the data collected
                • Find patterns in results
                    • Often with statistical analysis
                • From patterns propose a testable hypotheses

   A hypothesis is a tentative explanation of a set of
   observations. Hypotheses are tested by experiment

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                     Scientific Theory
          and                       Find Patterns, and
      Experiments                        Trends

                                      Formulate and
                                     Test Hypothesis

                         A theory provides explanations of observed phenomena
                         by predictions that can be tested experimentally.

A good scientist will generate as many questions as he or she answers
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                        Scientific Law
    • A scientific law is a concise verbal statement
      or a mathematical equation that summarizes a
      broad variety of observations and experiences.

Boyle’s Law states that for a given amount of gas at a constant
temperature, the volume of the gas varies inversely with its pressure.

    Einstein’s Theory                       Ideal Gas Law
      of Relativity                           PV = nRT
        E = mc2
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           Scientific Method Example
 Observations        • A researcher may observe that a
     and               large number of insects all have
                       three pairs of legs including flies,
                       beetles, grasshoppers and wasps.

Find Patterns, and
     Trends          • A conclusion may be drawn that
                       all insects have three pairs of
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           Scientific Method Example
 Observations        • Then after evaluating additional
     and               insects including cockroaches,
 Experiments           crickets, moths and bees

Find Patterns, and
     Trends          • A hypothesis might be formed
                       that all insects have three pairs
   Formulate and       of legs. However, a good scientist would not stop
  Test Hypothesis                     there. New hypotheses should be formed to
                                      further test the initial observation

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          Scientific Method Example
Test Hypothesis    • Perhaps immature moths should be considered,
                     as they are insects too, so they should have
                     three pairs of legs.
     and           • However, findings would determine that
 Experiments         caterpillars or immature moths do not have
                     three pairs of legs.

Re-Formulate and
 Test Hypothesis • Then the generalization becomes reformulated
                   into all adult insects have three pairs of legs.
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         What is chemistry(1.4)
• Chemistry is a study of the composition,
  structure, and properties of matter and of
  the changes that matter undergoes.
• Matter is the physical material of the
  – Matter is anything that has mass and occupies

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                    Atoms (1.4)
• Atoms are the smallest unit of matter that
  we associate with chemical behavior

• An Element is composed of a single type of
  – Examples
     • Gold     Au
     • Hydrogen H
     • Lead     Pb
               An atom is the smallest characteristic particle of an element.
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                  Chemical Symbols
    Chemical compounds are made up of atoms
    Symbols are a shorthand representation of the elements

•    Aluminum             Al        • Iron                          Fe
                                           – (from Latin Ferrum)
•    Bromine              Br
                                     •     Hydrogen                 H
•    Carbon              C
                                     •     Helium                    He
•    Calcium              Ca
                                     •     Oxygen                   O
•    Chlorine             Cl
                                     •     Potassium                K
•    Copper               Cu
                                           – (from Latin Kalium)
      – (from Latin Cuprum)
                                     • Sodium                        Na
• Fluorine               F                – (from Latin Natrium)

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          Chemical Symbols
• The symbols for the elements are 1 or 2
• The first letter is always capitalized
• The second Letter is always lower case

Hf is Hafnium       HF is Hydrogen Fluoride

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Currently Around 112 known elements
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                 Classification of matter
                            ALL MATTER

            Substances                                     Mixtures
                                                                   Mixtures can be
                                                                    separated by
                                                                   physical means
 elements            compounds
Composed of a         Composed of
single type of       atoms of two or
    atom            more elements, in
                       fixed ratios

                                        homogeneous           heterogeneous
                                          Uniform in               Varies in
                                        composition and         composition and
                                           properties              properties
                                      throughout mixture
                                  CHEM 1405
                                                              throughout mixture
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     Examples of Compounds

Water, H2O

                            Propane, C3H8

 Methane, CH4
                             Ethanol, CH3CH2OH
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Examples of Classification of Matter
•   Air
•   Water
•   Tap Water
•   Iodized Salt
•   Vegetable Soup

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                     Mass and weight (1.4)
     • Mass is the measure of the quantity of
       matter that an object contains
     • Weight measures a force

          On Earth           In Space                       On Moon
                                                        (1/6 earth’s gravity)
Weight 180 pounds          Weight-less                    30 pounds
Mass    82 kilograms       82 kilograms                   82 kilograms
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                                          Weight varies with gravity, mass does not
Physical and Chemical properties
• Physical properties: Properties that do not
  change the chemical nature of matter
  – are its physical characteristics and behavior
    such as color, odor, or hardness
• Chemical properties: Properties that do
  change the chemical nature of matter
  – describes how it reacts with other types of

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     Example Physical Properties
   Property                           Example
• Temperature                    Water for a bath is at 40 °C
• Mass                      A nickel has a mass of 5 grams.
• Color                                       Sulfur is yellow.
• Odor                                 Hydrogen sulfide stinks.
• Boiling point                        Water boils at 100 °C.
• Solubility                  Table salt dissolves in water.
• Heat capacity               Water has a high heat capacity.
• Hardness                    Diamond is exceptionally hard.
• Electrical conductance         Copper conducts electricity.
• Density                              Water has a density of
                           CHEM 1405   1.00 grams per milliliter
         Example Chemical Properties
Substance             Typical Chemical Property
Iron            Will rust (combine with oxygen to
                                      form iron oxide)
Carbon          Will undergo combustion (will combine
                       with oxygen to form carbon dioxide)
Silver          Will tarnish (combine with sulfur to form
                               silver sulfide)
Sodium          Will react violently with water to form
                hydrogen gas and a solution of
                sodium hydroxide
Nitroglycerin   Will explode (decompose, when detonated,
                              to a mixture of gases)
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            Physical Changes
• A physical change is one that does
  not entail any change in chemical
  – Water freezing to form ice
  – Iron melting in a blast furnace

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          Chemical Changes
• A chemical change involves a change in
  chemical composition
  – Iron Rusting
  – Natural gas burning

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                   States of matter
Water as example


GAS                     CHEM 1405
  Water as example        States of matter
           SOLID                        LIQUID

Property           Ice is solid H2O         Liquid H2O        Gaseous H2O

Rigidity                Rigid           Flows and Assumes    Fills completely
                                        Shape of Container   Any Container

Expansion on           Slight                     Slight        Expands
Heating                                                         infinitely

Compressibility        Slight                     Slight        Easily
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States of Matter

     CHEM 1405     31
Energy and Energy Conversion (1.6)
      • Potential energy is
        energy due to position or

      • Kinetic energy is the
        energy of motion.
                                 1 2
                             KE  mv

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            Electric Forces
• Like Charges repel
• Opposite Charges Attract

                   CHEM 1405   33
CHEM 1405

Class Meeting 2

    CHEM 1405     34
      Metric System, Calculations,
         Conversions, Density
•   7. What is the metric system of measurement? How does one convert between
    metric units and the units commonly used in the United States?
•   8. What is the difference between precision and accuracy in measurements?
•   9. Why is an understanding of significant figures important in chemistry?
    How do we determine the number of significant figures to report?
•   10. What is density?
•   11. What is the difference between temperature and heat?
•   12. How are the different temperature scales related to one another?

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        Modern Metric System
• International System of Units (SI)
  – SI comes from French Systeme International
  – Based on decimal system
     • All units related by factors of 10
                                            Makes is easier to use!
     • Prefixes denote magnitude

  – All measured quantities based on 7 base units

                         CHEM 1405                           36
          The Seven SI Base Units
Physical Quantity     Name of Unit   Symbol of Unit
Length                   meter             m
Mass                    kilogram          kg
Time                    second             s
Temperature              kelvin            K
Amount of substance      mole             mol
Electric Current        ampere             A
Luminous Intensity      candela           cd

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CHEM 1405   38
2.2. Precision and Accuracy

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2.3. Sampling Errors

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       2.4. Significant Figures
• 2.4.1. Multiplication and Division
• 2.4.2. Addition and Subtraction
• 2.4.3.

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2.5. Unit conversions

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2.6. Density

   CHEM 1405   43
  2.7. Energy - Temperature and
• 2.7.1. Temperature
  2.7.2. Heat

                   CHEM 1405      44

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