Scientific & Chemical
Fundamentals
Scientific & Chemical
Fundamentals
1
Chemistry & the Scientific Method
Matter : Classification & Properties
Mathematics / Arithmetic:
Dr. Ron Rusay
Fall 2007
Exponents, Significant Figures
Measurement & Units: (SI & metric)
Conversions and Relationships:
Dimensional Analysis: Density, Percent
VOCABULARY: Key Terms, Bold Style Learning
© Copyright 2003-2007 R.J. Rusay
© Copyright 1998-2007 R.J. Rusay
Textbook Reading
Science & The
Scientific Method
Chemical Foundations
1.1 Chemistry: An Overview
1.2 The Scientific Method
1.3 Units of Measurement
1.4 Uncertainty in Measurement
1.5 Significant Figures and Calculations
1.6 Dimensional Analysis
1.7 Temperature
1.8 Density
1.9 Classification of Matter
1
Some Possible Steps in the
Scientific Method
QUESTION
The difference between a scientific law and a scientific theory can,
at times, be confusing. For example, we will refer to the “Atomic
theory” or perhaps the “Law of Gravity.” Should the Law of
Gravity be changed to the Theory of Gravity?
1. Yes, no one can see gravity, it is better described as a theory.
2. No, scientific laws are based on summaries of many
observations and gravity observations are well known and
predictable.
3. Yes, gravity is better described as a theory because gravity
explains why masses attract each other and theories are about
explaining observations.
4. No, keep it as a law, laws offer explanations and gravity
explains why masses attract each other and laws are about
explaining observations.
Chemistry: The Study of Matter
In all of its forms & all of its behaviors
Sub-categories (not so distinct any longer)
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Organic: carbon
Inorganic: non-carbon
Organometallic: organic + inorganic
Analytical: what?, how much?, how pure?
Biological / Biochemistry: living organisms
Physical: energy, changes, rates
Nuclear: the nucleus
Environmental: interdisciplinary, eg.
Oceanography
© Copyright 1998-2007 R.J. Rusay
1.
•
•
Observations
qualitative
quantitative
2.
Formulating hypotheses
3.
Performing experiments
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4.
5.
possible explanation(s) for the observation
gathering new information
testing whether the hypotheses are valid
Developing a theory
Testing & Refining
Chemistry & Matter (Chemicals)
How many different chemicals do you
think have been reported in the
scientific literature?
A) 100,000
B) 1,000,000
C) 10,000,000
D) 100,000,000
E) 1,000,000,000
2
Chemistry & Matter:
Properties & States
1
• Physical vs. Chemical Properties
• Solid (s), Liquid (l), Gas (g)
• Homogeneous vs. Heterogeneous
Mixtures
• Organization of atoms/molecules:
atoms/elements → molecules/compounds
• Extensive vs. Intensive Properties
01_15
Matter
Organization of Matter
Heterogeneous
mixtures
Physical
methods
Homogeneous
mixtures (solutions)
Physical
methods
Pure substances
Classification
of Matter
Compounds
Chemical
methods
Elements
Atoms
Nucleus
Varies with amount (extensive) or does not vary
with amount (intensive)
© Copyright 1998-2007 R.J. Rusay
Electrons
Protons
Neutrons
Quarks
Quarks
leptons
muons , tau
muons,
tau,,
neutrinos
up,down, strange, charm, bottom, top
The effects of a
magnet on iron: filings
in a mixture and atoms
in a molecule.
3
Types of Mixtures
Mixtures have variable composition of two
or more components.
A homogeneous mixture is a solution (for
example, vinegar: water + acetic acid, or steel
& bronze: solid metals)
A heterogeneous mixture is, to the naked
eye, clearly not uniform (for example, a bottle
of ranch dressing with two layers: water + oil,
or two solids: iron and sulfur)
Elements & Compounds
Element: A substance that cannot
be broken into simpler substances
by chemical means, eg.
eg. Fe, Iron or
S8 Sulfur
Compound: A substance with a
constant composition that can be
broken down into elements only by
chemical processes,eg
processes,eg.. FeS,
FeS, Iron
(II) sulfide
QUESTION
Is a cup of coffee a homogeneous solution or a compound? Which
of the following agrees with your reasoning?
1. The coffee in the cup is a homogeneous solution because it
contains the same components throughout, but there are many
compounds dissolved to make coffee.
2. The coffee in the cup is a compound because it has a set
ratio of components that make it the same throughout.
3. The coffee in the cup is both a compound and a solution.
It looks the same throughout like a true solution, yet it always
has the same amount of each component.
4. The coffee in the cup is a heterogeneous solution not
homogeneous because it contains distinct, different
compounds dissolved to make coffee.
4
Measurement & Units
(SI units & common units in General Chemistry)
Units of Measure
1
• Quantitative vs. Qualitative
• MASS (Chem: gram; SI: kg)
• LENGTH (Chem: cm & others; SI: m)
• TEMPERATURE (Celsius & Kelvin; SI: K)
• VOLUME (Chem: mL; SI: Liter)
• CHEMICAL AMOUNT: Mole (mol)
Units
U.S.
SI
Chemistry
Mass (weight)
Pound (lb)
Kilogram (kg)
Volume
Gallon (gal)
u
Liter (L)
Temperature
Fahrenheit
(oF)
Mile (mi),
Feet(ft), Inches
(in)
Kelvin (K)
“ Gram”
(g, mg)
“ Liter”
(mL, L)
K & Celsius (oC)
Length
Time
Meter (m)
“ Meter”
(cm, mm, nm)
Second (s)
Second (s)
Mole (mol)
© Copyright 1998-2007 R.J. Rusay
Mass and Volume
Measurement
Mass Determination
(Weighing Devices: Balances)
5
01_05
1m3
Volumes of regular shapes
Volume
V=s3
h
1dm3= 1 L
V=lxwxh
1cm3= 1 mL
1 cm
1 cm
Liquid Measurement Tools
Numbers & Measurement
The Importance of Units
Measurement - quantitative observation
consisting of 2 parts
• Part 1 - number
• Part 2 - unit
Examples:
• 20 grams
• 6.63 × 10−34 joules / second
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Scale: Size & Comparison
Graphic Comparisons
Macroscopic vs. Microscopic
IBM financed Video:
http://www.wordwizz.com/imagendx.htm
How would you compare your lifespan?.. to that
of a dog? ….to the age of the earth?…How
about the age of mankind to that of all life?..
..the age of industrialized mankind to the age
of mankind?
Powers of Ten:
Scale
Language describes scale (prefixes)
Shorthand Prefixes
How many zeroes does yotta yotta yotta have?
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Commonly used prefixes in
Chemistry
Commonly used prefixes in Chemistry
The dark ones should be known from memory.
These should be known from memory.
QUESTION
Conveniently, a U.S. nickel has a mass of approximately 5 grams.
If you had one dollar’s worth of nickels what would be the mass
of the nickels in milligrams?
1.
2.
3.
4.
100 milligrams
50 milligrams
1,000 milligrams
100,000 milligrams
Scientific Notation &
Significant Digits
Scientific Notation: A single digit followed by a
decimal and a power of ten.
1000 milligrams (mg) = 1 gram (g)
Examples: 2,345 mL and 0.002340 g
2,345 mL = 2.345 x 10 3mL 0.002340 g = 2.340 x 10 -3 g
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