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CHEM 1405

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					Introduction to Chemistry
      CHEM 1405
        Section P02
       Dr. John Stankus
     jstankus@ccccd.edu
        Week 1 presentations




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




                        CHEM 1405                2
                      Grading
• 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
                         CHEM 1405                  3
              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)


                    CHEM 1405                 4
    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?




                                    CHEM 1405                                    5
       How science works
    The Scientific method (1.3)
Observations
                     Find Patterns, and
    and
                          Trends
Experiments


                       Formulate and
                      Test Hypothesis




                           Theory

               CHEM 1405                  6
 Observations and Experiments
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

                              CHEM 1405                                       7
                              Hypothesis
Find Patterns, and
     Trends


  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


                                      CHEM 1405                 8
                     Scientific Theory
      Observations
          and                       Find Patterns, and
      Experiments                        Trends


                                      Formulate and
                                     Test Hypothesis


                                           Theory
                         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
                               CHEM 1405                                  9
                        Scientific Law
    • A scientific law is a concise verbal statement
      or a mathematical equation that summarizes a
      broad variety of observations and experiences.

Example
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.
                              V1P1=V2P2


    Einstein’s Theory                       Ideal Gas Law
      of Relativity                           PV = nRT
        E = mc2
                                CHEM 1405                         10
           Scientific Method Example
 Observations        • A researcher may observe that a
     and               large number of insects all have
 Experiments
                       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
                       legs.
                              CHEM 1405                  11
           Scientific Method Example
                   (continued)
 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

                                  CHEM 1405                                12
          Scientific Method Example
                  (continued)
Test Hypothesis    • Perhaps immature moths should be considered,
                     as they are insects too, so they should have
                     three pairs of legs.
 Observations
     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.
        Theory
                             CHEM 1405                       13
         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
  universe
  – Matter is anything that has mass and occupies
    space




                     CHEM 1405                      14
                    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
  atom
  – Examples
     • Gold     Au
     • Hydrogen H
     • Lead     Pb
               An atom is the smallest characteristic particle of an element.
                           CHEM 1405                                     15
                  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)

                               CHEM 1405                               16
          Chemical Symbols
• The symbols for the elements are 1 or 2
  letters
• The first letter is always capitalized
• The second Letter is always lower case

Hf is Hafnium       HF is Hydrogen Fluoride




                    CHEM 1405               17
                     Elements




Currently Around 112 known elements
                         CHEM 1405    18
                 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
                                                                             19
CHEM 1405   20
     Examples of Compounds


Water, H2O




                            Propane, C3H8



 Methane, CH4
                             Ethanol, CH3CH2OH
                CHEM 1405                    21
Examples of Classification of Matter
•   Air
•   Water
•   Tap Water
•   Iodized Salt
•   Vegetable Soup




                     CHEM 1405    22
                     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
                              CHEM 1405                                     23
                                          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
    matter


                      CHEM 1405                     24
     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
                                                               25
                           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)
                       CHEM 1405                          26
            Physical Changes
• A physical change is one that does
  not entail any change in chemical
  composition
  – Water freezing to form ice
  – Iron melting in a blast furnace




                      CHEM 1405        27
          Chemical Changes
• A chemical change involves a change in
  chemical composition
  – Iron Rusting
  – Natural gas burning




                     CHEM 1405             28
                   States of matter
Water as example




                        LIQUID




                                            29
GAS                     CHEM 1405
                                    SOLID
                                                             GAS
  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
                                                              Compressed
                                      CHEM 1405                        30
States of Matter




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



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

                 CHEM 1405             32
            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?




                                  CHEM 1405                                 35
        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

                        CHEM 1405                     37
CHEM 1405   38
2.2. Precision and Accuracy




           CHEM 1405          39
2.3. Sampling Errors




       CHEM 1405       40
       2.4. Significant Figures
• 2.4.1. Multiplication and Division
• 2.4.2. Addition and Subtraction
• 2.4.3.




                    CHEM 1405          41
2.5. Unit conversions




        CHEM 1405       42
2.6. Density




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




                   CHEM 1405      44

				
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