Welcome to CHEMISTRY !!!

1
Welcome to CHEMISTRY !!!

• An Observational Science
• An Experimental Science
• A Laboratory Science
• An Interesting Science
• An Important Science
• A Hard Science

2
2H2 (g) O2 (g) 2 H2O (g) Energy

• Hydrogen and oxygen are diatomic gases!
• Water can be a gas!
• ENERGY was given off!-- This is characteristic of
  an Exothermic Reaction!
• This is a balanced chemical reaction!

3
CHEMISTRY
The Study of Matter and the Changes
that Matter Undergoes and The Energy Associated
with The Changes
4
Chemistry as the Central Science
Atmospheric Sciences
Physics
Oceanography
Medicine
Economics
Governments
Chemistry
People
Geology
Biology
Politics
Astronomy
Anthropology
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Chapter 1 Keys to the Study of Chemistry
1.1 Some Fundamental Definitions 1.2 Chemical
Arts and the Origins of Modern
Chemistry 1.3 The Scientific Approach Developing
a Model 1.4 Chemical Problem Solving 1.5
Measurement in Scientific Study 1.6 Uncertainty
in Measurement Significant Figures
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Definitions-I
Matter - The stuff of the universe books,
planets, trees, professors -
anything that has mass and
volume. Composition - The types and amounts of
simpler substances that make up a
sample of matter. Properties - The
characteristics that give each
substance a unique identity. Physical
Properties - are those the substance shows by
itself, without interacting with
another substance ( color,
melting point, boiling point,density, etc.)
Chemical Properties - are those that the
substance shows as it interacts
with, or transforms into, other
substances (flammability, corrosiveness, etc.)
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STATES OF MATTER -and the World Around US

• SOLID - The Earth
• LIQUID - Water
• GAS - The Atmosphere

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Fig. 1.2
9
Energy Involved in Phase Changes
Liberates Energy
Gas
Boiling
Condensation
Liquid
Melting
Freezing
Solid
Requires Energy
10
Definitions - II
Energy - The capacity to do work! Potential
Energy - The energy due to the position
of the object.Or Energy
from a chemical
reaction. Kinetic Energy - The energy due to
the motion of the
object.
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Fig. 1.3
12
Lavoisiers Experiment to Test His Hypothesis
that a Component of Air is Required for
Combustion.
Fig. 1.6
13
Scientific Approach Developing a Model
Observations Natural phenomena and measured
events universally
consistent ones can be stated as a natural law.
Hypothesis Tentative proposal that explains
observations.
Experiment Procedure to test hypothesis
measures one variable at
a time.
Model (Theory) Set of conceptual assumptions
that explains data
from accumulated experiments predicts related
phenomena.
Further Experiment Tests predictions based on
model.
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Units Used in Calculations
Length A car is 12 feet long, not 12 !
A person is 6 feet
tall, not 6 !
Area A carpet measuring 3 feet(ft) by 4 ft has
an area of ( 3 x 4 )( ft x
ft ) 12 ft2
Speed and Distance A car traveling 350
miles(mi) in
7 hours(hr) has a speed of 350 mi / 7 hr 50
mi / hr
In 3 hours the car travels 3 hr x 50 mi
/ hr 150 mi
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How to Solve Chemistry Problems
1) Problem States all of the information needed
to solve the Problem. 2)
Plan Clarify the known and unknown.
Suggest the steps needed to find the
solution. Develop
a roadmap solution. 3)Solution Calculations
appear in the same order as outlined. 4) Check
Is the result what you expect or at least in the
same order of magnitude! 5)
CommentAdditional information as needed.
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Conversion Factors Unity Factors - I
Equivalent factors can be turned into conversion
factors by dividing one side into the other!
1 mile 5280 ft or 1 1 mile / 5280 ft
5280 ft / 1 mi
1 in 2.54 cm or 1 1 in / 2.54 cm
2.54 cm / 1 in
In converting one set of units for another, the
one desired is on top in the conversion factor,
and the old one is canceled out!
convert 29,141 ft into miles!
29,141 ft x 1 mi / 5280 ft 5. 519 mi
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Conversion Factors - II
1.61 km 1 mi or 1 1.61 km / 1 mi
Convert 5.519 miles in to kilometers
5.519 mi x 1.61 km / mi 8.89 km
conversions in the metric system are easy, as 1
km 1000 m and 1 meter (m) 100
centimeters(cm) and 1 cm 10
millimeters(mm)
Therefore into cm and mm!
8.89 km x 1000m / 1 km 8890 m 8890 m x
100 cm / m 889000 cm
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Conversion Factors - III

• Multiple conversion factors
• Convert 3.56 lbs/hr into units of milligrams/sec
• 3.56 lbs/hr x (1kg/2.205 lbs) x(1000g/1kg) x
• (1000mg/1g) x (1hr/60 min) x (1min/60 sec)
• 
  448 mg/sec

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Conversion Factors - IVmetric volume to metric
volume

• 1.35 x 109 km3 volume of worlds oceans
• 1.35 x 109 km3 x (103 m/1 km )3 x ( 103 l/m3)
• 1.35 x 1021 liters
• conversion factors
• 1000m 1km
• 1000 l 1m3

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Calculate the mass of 1.00 ft3 of Lead
(density11.4g/ml)?
Conversion Factors - V

• 1.00 ft3 x (12 in/ft)3 x (2.54 cm/in)3
• 28,316.84659
  cm3
• 2.83 x 104 cm3 x 11.4 g/cm3 322,620.0000 g
• Ans. 3.23 x 105 g 3.23 x 102 kg

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Table 1. 2 (p. 17) SI - Base Units
Physical Quantity Unit Name
Abbreviation
Mass Kilogram
kg Length
meter m Time
second
s Temperature
Kelvin K Electric
current ampere
A Amount of substance mole
mol Luminous intensity
candela cd
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Table 1.3 Common Decimal Prefixes Used with SI
Units.
Prefix Prefix Number
Word Exponential Symbol

Notation
tera T 1,000,000,000,000
trillion 1012 giga
G 1,000,000,000
billion 109 Mega M
1,000,000 million
106 Kilo k
1,000 thousand
103 hecto h
100 hundred
102 deka da
10 ten
101 ----- ----
1 one
100 deci d
0.1 tenth
10-1 centi c
0.01 hundredth
10-2 milli m
0.001 thousandth
10-3 micro ????????????????????????????????
??????????????millionth 10-6 nano
n 0.000000001
billionth 10-9 pico p
0.000000000001 trillionth
10-12 femto f
0.000000000000001 quadrillionth
10-15
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Derived SI Units
Quantity Definition of Quantity
SI unit
Area Length squared
m2 Volume
Length cubed
m3 Density Mass per unit
volume kg/m3 Speed
Distance traveled per unit time
m/s Acceleration Speed
changed per unit time
m/s2 Force Mass times
acceleration of object kg m/s2

( newton,
N) Pressure Force per unit area
kg/(ms2)

( pascal,
Pa) Energy Force times distance
traveled kg m2/s2

( joule, J)
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Table 1.4 Common SI-English Equivalent
Quantities
Quanity SI Unit SI
English
Equivalent
Equivalent
Length 1 kilometer (km) 1000 (103) meters
0.62 miles (mi) 1
meter (m) 100 (102 ) centimeters
1.094 yards (yd)
1000 (103) millimeters
39.37 inches (in) 1 centimeter
(cm) 0.01 (10-2) meter 0.3937
inch Volume 1 cubic meter (m3) 1,000,000 (106)
35.2 cubic feet (ft3)
cubic
centimeters 1 cubic decimeter
1000 cubic centimeters 0.2642 gallon (gal)
(dm3)
1.057 quarts (qt)
1 cubic centimeter 0.001 dm3
0.0338 fluid ounce
(cm3) Mass 1 kilogram (kg)
1000 grams 2,205 pounds (lb)
1 gram (g) 1000
milligrams 0.03527 ounce (oz)
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Table 1.4 Contd Common SI-English Equivalent
Quantities
Quantity English to SI
Equivalent
Length 1 mile
1.61 km
1 yard 0.9144 m
1 foot (ft) 0.3048 m
1 inch 2.54 cm
(exactly!) Volume
1 cubic foot 0.0283 m3
1 gallon 3.785 dm3
1 quart
0.9464 dm3
1 quart 946.4 cm3
1 fluid ounce 29.6 cm3 Mass
1 pound (lb)
0.4536 kg
1 pound (lb) 453.6 g
1 ounce 28.35 g
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Some Volume Relationships in SI Units
Fig. 1.9
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Fig. 1.10A
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Some Interesting Quantities
Length Volume Mass
Fig 1. 11
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Like Sample Problem 1.3
The Volume of an irregularly shaped solid can be
determined from the volume of water it displaces.
A graduated cylinder contains 245.0 ml water.
When a small piece of Pyite, an ore of Iron, is
submerged in the water, the volume increases
to 315.8 ml. What is the volume of the piece of
galena in cm3 and in liters.
(p. 20)
30
Like Sample Problem 1.3
The Volume of an irregularly shaped solid can be
determined from the volume of water it displaces.
A graduated cylinder contains 245.0 ml water.
When a small piece of Pyite, an ore of Iron, is
submerged in the water, the volume increases
to 315.8 ml. What is the volume of the piece of
galena in cm3 and in liters.
Vol (ml) 315.8 ml - 245.0 ml 70.80 ml
Vol (cm3) 70.80 ml x 1 cm3/ 1 ml 4.6 cm3 Vol
(liters) 70.80 ml x 10 -3liters / ml 7.08 x
10 -2 liters
(p. 20)
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Definitions - Mass Weight
Mass - The quantity of matter an object contains
kilogram - ( kg ) - the SI base unit of mass, is
a platinum -
iridium cylinder kept in
Paris as a standard
Weight - depends upon an objects mass and the
strength of the gravitational
field pulling on it.
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Sample Problem 1.4 - I (p.22)
International computer communications will soon
be carried by optical fibers in cables laid along
the ocean floor. If one strand of optical fiber
weighs 1.19 x 10 -3 lbs/m, what is the total
mass (in kg) of a cable made of six strands of
optical fiber, each long enough to link New York
and Paris? (8.85 x 103 km).
Mass (kg) of Cable
1 km 103 m
2.205 lb 1 kg
1m 1.19 x 10 -3 lb
6 fibers 1 cable
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Sample Problem 1.4 - II
Length (m) of Fiber 8.85 x 103 km x 103m / km

8.85 x 106 m Mass (lb) of Fiber
8.85 x 106 m x 1.19 x 10-3 lb / 1m
1.05 x 104
lb Mass (lb) of cable 1.05 x 104 lb / 1 fiber
x 6 fibers / 1 cable
6.30 x 104 lb / cable Mass
(kg) of cable 6.30 x 104 lb / 1 cable x 1kg /
2.205 lb
2.86 x 104 kg / cable
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Densities of Some Common Substances
Substance Physical State
Density (g/cm3)
Hydrogen Gas
0.000089 Oxygen
Gas
0.0014 Grain alcohol Liquid
0.789 Water
Liquid
1.0 Table salt Solid
2.16 Aluminum
Solid
2.70 Lead Solid
11.3 Gold
Solid
19.3
Table 1.5 (p. 23)
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Sample Problem 1.5 - I
Lithium (Li) is a soft, gray solid that has the
lowest density of any metal. If a slab of Li
weighs 1.49 x 103mg and has sides that measure
20.9 mm by 11.1 mm by 12.0 mm, what is the
density of Li in g/ cm3 ?
(p. 23)
36
Sample Problem 1.5 - II
1 g
Mass (g) of Li 1.49 x 103 mg x
1.49 g Length (cm) of one side 20.9 mm x
1cm / 10 mm 2.09 cm Similarly, the other side
lengths are 1.11 cm and 1.20 cm Volume (cm3)
2.09 cm x 1.11 cm x 1.20 cm 2.78 cm3
Density of Li
0.536 g/cm3
103 mg
1.49 g
2.78 cm3
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Like Sample Problem 1. 5 - Density of a Metal
Problem Cesium is the most reactive metal in the
periodic table, what is its density if a
3.4969 kg cube of Cs has sides of 125.00 mm
each? Plan Calculate the volume from the
dimensions of the cube, and calculate the
density from the mass and volume. Solution
38
Like Sample Problem 1. 5 - Density of a Metal
Problem Cesium is the most reactive metal in the
periodic table, what is its density if a
3.4969 kg cube of Cs has sides of 125.00 mm
each? Plan Calculate the volume from the
dimensions of the cube, and calculate the
density from the mass and volume. Solution
length 125.00 mm 12.500 cm
mass 3.4969 kg x 1000g/kg 3,496.9 g
Volume (length)3 (12.500 cm)3 1,953.125 cm3
39
Like Sample Problem 1. 5 - Density of a Metal
Problem Cesium is the most reactive metal in the
periodic table, what is its density if a
3.4969 kg cube of Cs has sides of 125.00 mm
each? Plan Calculate the volume from the
dimensions of the cube, and calculate the
density from the mass and volume. Solution
length 125.00 mm 12.500 cm
mass 3.4969 kg x 1000g/kg 3,496.9 g
Volume (length)3 (12.500 cm)3 1,953.125 cm3
mass 3496.9 g
density
1.7904 g/ml
volume 1,953.125 cm3
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Fig 1.12
41
Fig 1.13
42
Temperature Scales and Interconversions
Kelvin ( K ) - The Absolute temperature scale
begins at absolute zero
and only has positive values.
Celsius ( oC ) - The temperature scale used by
science, formally
called centigrade and most
commonly used scale around the world,
water freezes at 0oC, and boils
at 100oC.
Fahrenheit ( oF ) - Commonly used scale in
America for our
weather reports, water freezes at 32oF,
and boils at 212oF.
T (in K) T (in oC) 273.15 T (in oC) T (in
K) - 273.15
T (in oF) 9/5 T (in oC) 32 T (in oC) T
(in oF) - 32 5/9
43
Temperature Conversions
The boiling point of Liquid Nitrogen is - 195.8
oC, what is the temperature in Kelvin and
degrees Fahrenheit?
T (in K) T (in oC) 273.15

The normal body temperature is 98.6oF, what is it
in Kelvin and degrees Celsius?
T (in oC) T (in oF) - 32 5/9

44
Temperature Conversions
The boiling point of Liquid Nitrogen is - 195.8
oC, what is the temperature in Kelvin and
degrees Fahrenheit?
T (in K) T (in oC) 273.15 T (in K) -195.8
273.15 77.35 K 77.4 K
T (in oF) 9/5 T (in oC) 32 T (in oF) 9/5 (
-195.8oC) 32 -320.4 oF
The normal body temperature is 98.6oF, what is it
in Kelvin and degrees Celsius?
T (in oC) T (in oF) - 32 5/9

45
Temperature Conversions
The boiling point of Liquid Nitrogen is - 195.8
oC, what is the temperature in Kelvin and
degrees Fahrenheit?
T (in K) T (in oC) 273.15 T (in K) -195.8
273.15 77.35 K 77.4 K
T (in oF) 9/5 T (in oC) 32 T (in oF) 9/5 (
-195.8oC) 32 -320.4 oF
The normal body temperature is 98.6oF, what is it
in Kelvin and degrees Celsius?
T (in oC) T (in oF) - 32 5/9 T (in oC)
98.6oF - 32 5/9 37.0 oC
T (in K) T (in oC) 273.15 T (in K) 37.0 oC
273.15 310.2
46
The Number of Significant Figures in
a Measurement Depends Upon the Measuring Device
Fig 1.15A
47
Rules for Determining Which Digits are
Significant
All digits are significant, except zeros that are
used only to position the decimal point.
1. Make sure that the measured quantity has a
decimal point. 2. Start at the left of the number
and move right until you reach the first
nonzero digit. 3. Count that digit and every
digit to its right as significant. Zeros that
end a number and lie either after or before the
decimal point are significant thus 1.030 ml has
four significant figures, and 5300. L has four
significant figures also. Numbers such as 5300 L
is assumed to only have 2 significant figures. A
terminal decimal point is often used to clarify
the situation, but scientific notation is the
best!
48
Examples of Significant Digits in Numbers
Number - Sig digits Number
- Sig digits
0.0050 L two 1.34000 x 107
nm six 18.00 g four
5600 ng two 0.00012 kg
two 87,000 L
two 83.0001 L six 78,002.3
ng six 0.006002 g four
0.000007800 g four 875,000 oz
three 1.089 x 10 -6L
four 30,000 kg one
0.0000010048 oz five 5.0000 m3 five
6.67000 kg
six 23,001.00 lbs seven 2.70879000 ml
nine 0.000108 g three
1.0008000 kg eight 1,470,000 L
three 1,000,000,000 g one
49
Rules for Significant Figures in Answers
1. For multiplication and division. The number
with the least certainty limits the certainty of
the result. therefore, the answer contains the
same number of significant figures as there are
in the measurement with the fewest significant
figures. Multiply the following numbers
9.2 cm x 6.8 cm x 0.3744 cm 23.4225 cm3 23 cm3
2. For addition and subtraction. The answer has
the same number of decimal places as there are
in the measurement with the fewest decimal
places. Example, adding two volumes 83.5 ml
23.28 ml 106.78 ml 106.8 ml Example
subtracting two volumes 865.9 ml -
2.8121393 ml 863.0878607 ml 863.1 ml
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Rules for Rounding Off Numbers
1. If the digit removed is more than 5, the
preceding number increases by 1 5.379 rounds
to 5.38 if three significant figures are retained
and to 5.4 if two significant figures are
retained. 2. If the digit removed is less than 5,
the preceding number is unchanged 0.2413
rounds to 0.241 if three significant figures are
retained and to 0.24 if two significant figures
are retained. 3.If the digit removed is 5, the
preceding number increases by 1 if it is odd and
remains unchanged if it is even 17.75 rounds to
17.8, but 17.65 rounds to 17.6. If the 5 is
followed only by zeros, rule 3 is followed if
the 5 is followed by nonzeros, rule 1 is
followed 17.6500 rounds to 17.6, but 17.6513
rounds to 17.7 4. Be sure to carry two or more
additional significant figures through a
multistep calculation and round off only the
final answer. (In sample problems and follow-up
problems, we round off intermediate steps of a
calculation to show the correct number of
significant figures.
51
Precision and Accuracy Errors in
Scientific Measurements
Precision - Refers to reproducibility or How
close the measurements are to
each other. Accuracy - Refers to how close a
measurement is to the real
value. Systematic error - produces values that
are either all higher
or all lower than the actual value. Random
Error - in the absence of systematic error,
produces some
values that are higher and some that
are lower than the actual value.
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Fig. 1.17