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					       Chapter 1: Introduction


        Classification of Matter
Matter can exist in different forms or phases:

               (1) States of Matter
Chapter 1: Introduction


Classification of Matter
             Chapter 1: Introduction


              Classification of Matter

         Defined   Defined   Distance     Compressible?
         shape?    volume?   between
                             molecules?

Solid


Liquid


Gas
                  Chapter 1: Introduction


                   Classification of Matter
(2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

    Molecules:




     atom
                  Chapter 1: Introduction


                   Classification of Matter
(2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

    Elements:
                  Chapter 1: Introduction


                   Classification of Matter
(2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

    Compounds:
                  Chapter 1: Introduction


                   Classification of Matter
(2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

    Pure Substance:
                  Chapter 1: Introduction


                   Classification of Matter
(2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

    Mixtures:
                  Chapter 1: Introduction


                   Classification of Matter
(2) Molecules, Elements, Compounds, Pure Substances, and Mixtures

 Homogeneous Mixtures         <->       Heterogeneous Mixtures




                                                        Oil on water




    Air
                                                              HW: 1, 2
                    Chapter 1: Introduction


                     Classification of Matter
  (2) Molecules, Elements, Compounds, Pure Substances, and Mixtures




Phase state?

Molecules
or atoms?

Compound?

Mixture?

 - what kind?
                                                       HW: 9, 15
                Chapter 1: Introduction

      Homogenous or Heterogeneous Mixtures?
  Vinaigrette                  Mud
                                             Granite




Coffee - a        Coffee - b         Brass      Water and flour
Chapter 1: Introduction
             Chapter 1: Introduction

       Mixtures can be separated
                   ... for example by

Filtration                              Chromatography




                Distillation
                Chapter 1: Introduction


                 Properties of Matter

Physical Properties & Changes

 → no change in identity or composition of substance



Chemical Properties & Changes
 → how a substance reacts to form a different substance
                          HW: 17, 19
Chapter 1: Introduction


Properties of Matter
       Burning of wood:




       Melting of ice:
                       Chapter 1: Introduction

Physical of Chemical Property?

              Zinc (Zn):

          ●   silver-grey metal

          ●   melting point: 420oC

          ●reacts with oxygen to form
          Zinc oxide (ZnO)

          ●   density (25oC) = 7.13 g/cm3

          ●generates hydrogen when
          dissolved in sulfuric acid
                    Chapter 1: Introduction

Physical or Chemical Process?

     Sugar dissolving in water.




                                  The picture on the left represents

                                  a) compounds in the gas phase
                                  b) elements in the gas phase
                                  c) molecules in the gas phase
                                  d) a heterogeneous mixture of
                                  elements
                                  e) a mixture of molecules in the
                                  liquid phase
                Chapter 1: Introduction



Intensive Properties…
                        …are independent of the amount of substance


Extensive Properties…
                     …depend on the amount of substance



Boiling/melting point (bp/mp)

Mass

Volume

Density
                Chapter 1: Introduction


A gold nugget (1cm x 0.5 cm x 0.7 cm) has a density of 19.3 g/cm3.
A jeweler decides to use this gold nugget to make a perfect gold
Sphere with a diameter of 0.4cm. What is the density of this sphere?
     Chapter 1: Introduction


Units of Measurement: Temperature




                 K = OC + 273
                    Chapter 1: Introduction


                     Units of Measurement

Système International d'Unités (SI units)



        Mass                                         kilogram    kg
        Length                                       meter       m
        Time                                         second      s
        Temperature                         Kelvin              K
        Amount of a substance                        mole        mol
                      Chapter 1: Introduction


                      Units of Measurement
Prefixes used in the metric system:

        You ABSOLUTELY MUST know these (Table 1.5 page 14):

                      Giga                  G   gigameter (Gm)    = 109 m
                              Mega          M   megameter (Mm)    = 106 m
                                     Kilo   K   kilometer (Km)    = 103 m
                                                meter (m)         =1m
                               Deci         d   decimeter (dm)    = 10-1 m
                               Centi        c   centimeter (cm)   = 10-2 m
                              Milli         m   millimeter (mm)   = 10-3 m
                      Micro                 µ   micrometer (µm)   = 10-6 m
               Nano                         n   nanometer (nm)    = 10-9 m
        Pico                                p   picometer (pm)    = 10-12m
Femto                                       f   femtometer (fm)   = 10-15m
                 Chapter 1: Introduction


          Units of Measurement: Derived Units


Volume:
                        1m   (1 m)3 = 1m3 = 1cubic meter

          1m     1m




                  1cm        (1 cm)3 = 1cm3 = 1cubic centimeter = 1mL
           1cm   1cm
                                           HW: 24, 29
          Chapter 1: Introduction


Units of Measurement: Derived Units


                          mass
               Density =
                         volume


●   Generally expressed as g/mL or g/cm3

●   Depend on temperature
                                                                              HW: 49, 52
                       Chapter 1: Introduction


                        Dimensional Analysis

Converting inches into cm:
                                       Conversion factor:
                                       same quantity but in different units

                         2.54cm
                23.2in          58.9cm
                           1in
       - the units to be eliminated go on opposite sides of the fraction

Converting m/min into m/s:

                      m    1 min         m
               1.2       ×       = 0.020
                     min    60 s         s
                                     Conversion factor
                                Chapter 1: Introduction


                                 Dimensional Analysis
More than one conversion:
 A car travels 12 km per liter of gasoline. How many many miles per gallon will it go?
  =>         Convert 12 km/L into mi/gallon
  =>         first, convert length units: km into mi, second, convert volume units: L into gallons


                              1 mi
                   km       1.61 km
       (1)      12    ×   or
                    L
                            1.61 km
                              1 mi
                                  Chapter 1: Introduction


                                  Dimensional Analysis
More than one conversion:
 A car travels 12 km per liter of gasoline. How many many miles per gallon will it go?
  =>         Convert 12 km/L into mi/gallon
  =>         first, convert length units: km into mi, second, convert volume units: L into gallons


                   km     1 mi         mi
       (1)      12    ×         = 7.45
                    L   1.61 km        L

                                   1 gal
                   mi             3.785 L
       (2)    7.45    ×      or
                   L
                                  3.785 L
                                   1 gal
                         Chapter 1: Introduction


                           Dimensional Analysis

More than one conversion:
 A car travels 12 km per liter of gasoline. How many many miles per gallon will it go?
  =>    Convert 12 km/L into mi/gallon
  =>    first, convert length units: km into mi, second, convert volume units: L into gallons

            km     1 mi         mi
  (1)    12    ×         = 7.45
             L   1.61 km        L



             mi   3.785 L          mi                       mi       Correct number
  (2)   7.45    ×         = 28.198                   = 28              of sig. figs.
             L     1 gal           gal                      gal
                             Chapter 1: Introduction


                              Dimensional Analysis
More than one conversion:
 A car travels 12 km per liter of gasoline. How many many miles per gallon will it go?
  =>    Convert 12 km/L into mi/gallon
  =>    first, convert length units: km into mi, second, convert volume units: L into gallons
  =>    with more PRACTICE you can combine steps (1) and (2):




                   km     1 mi    3.785 L      mi
                12    ×         ×         = 28
                    L   1.61 km    1 gal       gal
                        Chapter 1: Introduction


                          Dimensional Analysis

Conversions involving squared and cubic units:
 The volume of a container is 5.3 m3. What is the volume in cm3?
  =>    Convert m3 into cm3



                      100 cm
           5.3 m3 ×
                       1m



                  Units must match in order to cancel out!
                        Chapter 1: Introduction


                          Dimensional Analysis

Conversions involving squared and cubic units:
 The volume of a container is 5.3 m3. What is the volume in cm3?
  =>    Convert m3 into cm3




                 3 1003 cm3
           5.3 m ×          = 53,00000 cm3
                    13 m3
                            = 5.3 × 1000000 cm3
                                  = 5.3 × 106 cm3

                Units must match = cube both number AND unit !
                                                                 HW: 35
                     Chapter 1: Introduction


                  Uncertainty in Measurement


 Inexact Numbers          Obtained by measurement




 Exact Numbers            Value is known precisely



The temperature of the asphalt   Mass of 1L of milk?   The number of mm in
on Randall Drive today?                                one yd of speaker
                                                       cable ?
                     Chapter 1: Introduction


                  Uncertainty in Measurement

good accuracy       poor accuracy        poor accuracy      good accuracy
good precision      good precision       poor precision     poor precision




Accuracy: how do the measured values agree with the “true” value?

Precision: how reproducible is the measurement?
                     Chapter 1: Introduction


                        Significant Figures

Which digits count?

(a) All significant digits in a number

Zeros...
     (b) ...between nonzero digits count
     (c) ...in the beginning of a number never count
     (d) ...in the end of a number count (compare lab manual)


0.04305    4 sig figs             0.34000   5 sig figs

1.04305    6 sig figs             45,000    2 sig figs
                 Chapter 1: Introduction


                        Significant Figures
0.04305    4 sig figs           0.34000        5 sig figs

1.04305    6 sig figs           45,000         2 sig figs


This is easiest to see when written in exponential notation:


 0.04305 = 4.305 x 0.01          = 4.305 x 10-2
 0.34000 = 3.4000 x 0.1          = 3.4000 x 10-1

 45,000 = 4.5 x 10000            = 4.5 x 104
                     Chapter 1: Introduction


                        Significant Figures

●   Final result is only as accurate as the least accurate measurement

●   The least accurate measurement determines the number of sig. figs.


    (1) Division and Multiplication:

          volume = 1.32cm x 1.1cm x 3.540cm = 5.14008cm3 = 5.1cm3
                                 Answer rounded to 2 sig. figs.

       velocity = 342 m / 32 s = 10.6875 m/s = 11 m/s
                                   Answer rounded to 2 sig. figs.

       Number with fewest sig. figs. determines sig. figs. of answer
                     Chapter 1: Introduction


                        Significant Figures

●   Final result is only as accurate as the least accurate measurement

●   The least accurate measurement determines the number of sig. figs.


    (2) Addition and Subtraction

         1.234                Number with fewest decimal places
    +    0.124                (NOT sig. Figs.) determines answer
    +    320.13
    -    56.1
    = 265.388
    = 265.4     answer rounded to 1 decimal point

				
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