CHEMISTRY 100     CHAPTER 1 LECTURE NOTES
Chemistry is the study of the composition, structure, and properties of matter and of changes that occur
in matter.  Matter can be understood as the building block of the universe. It is anything that takes up
space and has mass.  Matter exists in three different states.

Three Physical States of Matter.
STATE SHAPE VOLUME COMPRESSIBLE
Solid Fixed Fixed No
Liquid Fixed Fixed  Relatively incompressible
Gas No fixed shape No fixed volume Yes

Atom the smallest distinctive units in a sample of matter. Atoms are electrically neutral.

Molecule a definite group of atoms that are chemically bonded together that is, tightly connected by
                 attractive forces.  Molecules are electrically neutral.

Composition  refers to the types and relative proportions in a sample of matter.

Physical property: a characteristic that can be observed for a material without changing its chemical
                                   identity. (e.g. boiling point, melting point, density)

Chemical property: properties that describe a substance's composition and its reactivity; how the
                                   substance reacts, or changes into other substances.

Physical change: processes that occur without a change in chemical composition or identity.
                               Substances do not change into other substances in a physical change.
                               Melting candle wax:  C50H102(s) ---> C50H102(l)

Chemical change: processes that result in a change in chemical composition or identity.
                                 Chemical processes alter substances to other substances.
                                 Burning candle wax:  2 C50H102(s) + 151 O2(g) ---> 100 CO2(g) + 102 H2O(g)

Matter:   Matter is anything which takes up space and has mass.  It can be categorized into two different classes.
        1.  Substance:  Matter which cannot be separated into other kinds of matter by a physical process.
        2.  Mixture:  Matter which can be separated into other kinds of matter by a physical process.

   Substances fall into two sub-categories.
        1.  Element:  A substance which cannot be decomposed into a simpler substance by a chemical process.
            a.  Metals
            b.  Nonmetals
            c.  Metalloids
        2.  Compound:  A substance composed of more than one element chemically combined.
            a. Ionic (Also referred to as salts.)    Ionic compounds are composed of metals and nonmetals.
            b. Covalent  (Also referred to as molecules.)  Molecular compounds are composed of only nonmetals.

   Mixtures also fall into two sub-categories.
        1.  Homogeneous:  (Also called solutions.)  A mixture which is uniform in its properties throughout.
            a.  Gaseous solutions -  Air is an example of a gaseous mixture.
            b.  Liquid solutions  -   Salt water is an example of a liquid solution.
            c.  Solid solutions  -  Brass is an example of a solid solution.

        2.  Heterogeneous:  A mixture with physically distinct parts, each with different properties.


SCIENTIFIC METHOD
Hypothesis: a tentative explanation of some regularity of nature.

Experiment:  an observation of natural phenomena carried out in a controlled manner so that the results can be duplicated
and rational conclusions obtained.

Data:  Facts obtained from observation and measurements during an experiment.  Data should be reproducible.

Scientific Law:  a concise statement or mathematical equation about a fundamental relationship or regularity of nature.

Theory: a tested explanation of basic natural phenomena.


SCIENTIFIC MEASUREMENTS
 
Some Basic SI 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

LENGTH
The SI unit of length is the meter (m), a unit about 10% longer than a yard.  One meter is 39.37 inches

VOLUME
Volume is the amount of space occupied by an object.  The SI unit for length is the meter and the SI-derived unit of volume is
 the cubic meter (m3 ).  One cubic meter is about 264.2  U.S. gallons.  Measurements of volume in the laboratory are normally
made in the liter (L).   A liter is the volume occupied by one cubic decimeter (dm3 ).

    1 L = 1 dm3 = 1 x 10-3 m3             or 1 cm3 = 1 mL

MASS
Mass is the quantity of matter in an object.  The SI unit is the kg which is about 2.2 pounds.

TIME
The SI unit for time is the second.

TEMPERATURE
Temperature is a measure of how hot or cold an object is relative to another object.  It is the property of an object
that measures the amount of random energy of motion of its molecules and determines the direction of spontaneous
heat flow.

The SI unit of temperature is the Kelvin (K).

Three Scales for Measuring Temperature
Reference Fahrenheit Celsius Kelvin
Water boiling point 212 oF 100 oC 373.15 K
Water freezing point 32 oF 0 oC 273.15 K

     (Note:  -40 oF =  -40 oC =  233.15 K)

Interconversions Between Temperature Scales
K = 273.15 + oC                           [The temperature intervals of Celsius and Kelvin are equal.]
oF = (1.8 x oC) + 32  or  [9/5 oC] + 32
oC = (oF - 32)/1.8  or  [oF - 32](5/9)

EXAMPLE
        98.6 oF = ? K
      oC = [oF - 32](5/9)
      oC = [98.6 oF - 32](5/9) = 37.0 oC
        K = 273.15 + oC = 273.15 + 37.0 oC = 310.2 K


PREFIXES FOR MULTIPLES OF SI UNITS
Some measurements are extremely small (bond distances in molecules) while others are extremely large (distances
between planets).  Prefixes are therefore utilized that modify these measurements in decimal fashion so as to make them
more convenient.
 
Some Common SI Prefixes
Multiple Prefix Symbol Example equivalents using the  gram as the base unit
106 mega M 1 Mg = 1 x 106 g = 1,000,000 g
103 kilo k 1 kg = 1 x 103 g = 1000 g
10-1 deci d 1 g = 1 x 101 dg = 10 dg
10-2 centi c 1 g = 1 x 102 cg = 100 cg
10-3 milli m 1 g = 1 x 103 mg = 1000 mg
10-6 micro m 1 g = 1 x 106 mg = 1,000,000 mg
10-9 nano n 1 g = 1 x 109 ng = 1,000,000,000 ng
10-12 pico p 1 g = 1 x 1012 pg = 1,000,000,000,000 pg


SI UNIT CONVERSIONS

SAMPLE PROBLEMS
Convert each of the following so that the power of ten is replaced by a prefix.
    1.    3.88 x 10-2 g = ?              (3.88 cg)
    2.    1.72 x 10-9 s = ?              (1.72 ns)
    3.    8.06 x 103 L = ?              (8.06 kL)
    4.    6.95 x 10-3 mol = ?          (6.59 mmol)

SAMPLE PROBLEMS
Convert each of the following.
    1.    157.63 kg =   ? g                (1.5763 x 105 g)
    2.    2.385 x 10-8 ns =   ? s           (2.385 x 10-17 s)


PRECISION AND ACCURACY IN MEASUREMENT
Precision: the closeness of a set of values obtained from identical measurements of a quantity or the repeatability
                    of measurements.
Accuracy: the closeness of a single measurement to its true value or the correctness of measurements.
Significant figures: those digits in a measured number (or result of a calculation with measured numbers) that
                                     include all certain digits plus a final one having some uncertainty.

All measurements have uncertainty.

Report measurements by recording all certain digits plus the first uncertain digit.

NUMBER OF SIGNIFICANT FIGURES
Rules of significant figures
A.  All Non zero digits are significant  (843.47 has five sig. fig.)
B.  Zeros -
         Leading zeros - not significant (zeros to the left of number; 0.0032 has two sig. fig.)
         Captured zeros - significant (zeros between non zero numbers; 2.003 has four sig. fig.)
         Trailing or terminal zeros- significant only if number contains a decimal point, otherwise not (zeros to right of
                                                            number;  9.0 has two sig. fig.)

Exact numbers - infinite number of sig. fig. (There are exactly 12 inches in 1 foot; both 12 and 1 are exact numbers and
                              therefore have an infinite number of sig. fig.)

Rules for significant figures in calculations
1. Multiplication/Division -
    the answer has same number of significant figures as the value in the operation with the least number of
   significant figures   (43.7 x 1.9932 = 87.10284; correct answer, 87.1,  has three sig. fig.)
2. Addition/Subtraction -
    the answer has same number of decimal places as the value in the operation with the least number of decimal places
    (27.35 + 1.4 = 28.75; correct answer, 28.8 has three sig. fig. because the least precise only has one decimal place.)

Exact numbers  have no bearing on the number of sig. fig. and are not considered when determining the number of
                             sig. fig. in an answer.

Rounding  If the first digit to be removed is less than 5, simply remove the unwanted digits.
                    The number 6.7495 rounded to two sig. fig. is 6.7 because 4 is less than 5.

                    If the first digit is 5 or more, increase the preceding digit by one.
                    The number 3.350 rounded to two sig. fig. is 3.4 because the first digit removed is 5.
                    The number 18.827 rounded to four sig. fig. is 18.83 because 7 is greater than 5.

ORDER of OPERATION:
Please             Parenthesis
Excuse            Exponents
My
Dear                Multiplication & Division
Aunt
Sally                Addition & Subtraction

SAMPLE PROBLEMS:
Perform the following operations and give answers in the correct number of significant figures.

A.     4.184 x 100.62 x (25.27 - 24.16) = ?            [467.]

B.   8.925 - 8.904 x 100 = ?            [0.24]
               8.925

C.     (9.04 - 8.23 + 21.954 + 81.0) / 3.1416 =?             [33.04]

D.       9.2 x 100.65  = ?                [75.]
          8.321 + 4.026

E.     0.1654 + 2.07 - 2.114 = ?                [0.12]

F.     8.27(4.987 - 4.962) = ?                [0.21]

G.        9 .5 + 4.1 + 2.8 + 3.175  = ?                 [4.9]
                        4

H.      9.025 - 9.024  (100) = ?                [0.01]
              9.025


CONVERTING FROM ONE UNIT TO ANOTHER

The procedure used to convert from one unit of measure to another is referred to a the
factor-label method, or dimensional analysis.   This procedure involves relating two different
units of measurement by an equivalence statement.   The units "week" and "day" are different
but both are related to time.  It can be said that 1 week is equivalent to 7 days.
This can be written as:  1 week = 7days.  Thus, a ratio of either 1 week/7 days or
7 days/1 week is established based upon the equivalence statement.

CONVERSION FACTORS
Length SI unit: meter (m)
1 m = 39.37 in
1 m = 1.0936 yd
1 in = 2.54 cm (exact)
1 mi = 5280 ft
1 mi = 1.6093 km		 Volume (derived) SI unit: cubic meter (m3)
1 L = 1 x 10-3 m3 = 1 dm3
1 L = 1.0567 qt
1 gal = 4 qt = 3.7854 L
1 cm3 = 1 mL
1 in3 = 16.4 cm3		 Mass SI unit: kilogram (kg)
1 kg = 2.2046 lb
1 lb = 16 oz = 453.59 g
1 oz = 28.349 g
1 amu = 1.66054 x 10-27 kg
Temperature SI unit: Kelvin (K)
0 K = -273.15 oC = -459.67 oF
K = 273.15 + oC
oF = (1.8 x oC) + 32 or [9/5 oC] + 32
oC = (oF - 32)/1.8 or [oF - 32](5/9)		 Pressure (derived) SI unit: Pascal (Pa)
1 Pa = 1 N/m2 = 1 kg/(m.s2)
1 atm = 101,325 Pa
1 atm = 760 mmHg = 760 Torr
1 atm = 29.921 in Hg = 1.01325 bar
1 atm = 14.696 lb/in2 = 14.696 psi		 Energy (derived) SI unit: Joule (J)
1 J = 1 (kg.m2)/s2
1 J = 0.23901 cal
1 J = 1 C x 1 V
1 cal = 4.184 J
1 eV = 1.602 x 10-19 J

EXAMPLE
How many calories are in 327kJ?
    1 cal = 4.184 J    or  1 cal/4.184 J
    (327 kJ)(1000 J/kJ)(1 cal/4.184 J) = 7.82 x 104 cal

SAMPLE PROBLEMS
    1.    25.00 gal = ? L         (94.63 L)
    2.    10.0 ft = ? cm         (305. cm)
    3.    The human head weighs about 8.00 lb. What is this in g?         (3.63 x 102 g)
    4.    How many mL are there in 3.87 x 104 m3?         (3.87 x 1010 mL)
    5.    14.3 cm3 = ? yd3          (1.87 x 10-5 yd3)
    6.    65 mph = ? m/s         (29 m/s)
    7.    263.2 cubic centimeter = ft3         (9.293 x 10-3 ft3)
    8.    The earth rotates around its axis with a velocity such that a person standing at the equator is moving at
            a rate of 1039 mph.
            A. What is this speed in m/s?         [464.5 m/s]
            B.  Since it takes 24.0 hours for the earth to make one rotation, what is the circumference of the earth in
                  miles?   [2.49 x 104 miles]


DENSITY

Density (d) is the ratio of mass to volume.    d = mass/volume

SAMPLE PROBLEMS
What is the density of a sample of metal which has a mass of 118.26 g and a volume of 43.8 mL.
    [2.70 g/mL]

SAMPLE PROBLEMS
What is the mass in grams of a 9.00 cm3 piece of lead? The density of lead is 11.3 g/cm3.
    [102. g]

SAMPLE PROBLEMS
What is the volume of a sample of mercury which has a mass of 938.22 g and a density of 13.5 g/mL?
    [ 69.50 mL]

SAMPLE PROBLEMS
When a 26.048 g sample of metal was placed in a graduated cylinder containing water, the water level rose
from 25.0 mL to 28.31 mL. What is the density of the metal?
    [7.9 g/mL]

SAMPLE PROBLEMS
What is the mass of the snow (in tons) on a 150 x 45 flat roof after a 6.0 inch snowfall?
Assume that 11 inches of snow are equivalent to 1.0 in of water.
Density of water is 1 g/mL            [9.6 tons]


INTENSIVE AND EXTENSIVE PROPERTIES
1. Intensive Properties - properties that are independent of the amount of material (density, color, temperature).
2. Extensive properties - properties that are dependent on the amount of material (mass, volume, number of moles)