Chapter 1 Introduction to Chemistry

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Chapter 1
“Introduction to
Chemistry”
Charles Page High School
Pre-AP Chemistry
Stephen L. Cotton
1
What is Chemistry?
 Chemistry
is the study of the
composition of “matter” – (matter is
anything with mass and occupies
space), its composition, properties, and
the changes it undergoes.
 Has a definite affect on everyday life taste of foods, grades of gasoline, etc.
 Living and nonliving things are made of
matter.
2
Chemistry is the
study of the
composition,
structure, and
properties of matter
and the changes it
undergoes – such
as burning fuels.
C2H5OH + 3 O2  2 CO2 + 3 H2O + Energy
Reactants
3

Products
5 Major Areas of Chemistry
Analytical Chemistry- concerned with
the composition of substances.
2) Inorganic Chemistry- primarily deals
with substances without carbon
3) Organic Chemistry- essentially all
substances containing carbon
4) Biochemistry- Chemistry of living things
5) Physical Chemistry- describes the
behavior of chemicals (ex. stretching);
involves lots of math!
Boundaries not firm – they overlap and interact
1)
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- Page 8
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What is Chemistry?
 Pure
chemistry- gathers knowledge for
the sake of knowledge
 Applied Chemistry- is using chemistry
to attain certain goals, in fields like
medicine, agriculture, and
manufacturing – leads to an application
* Nylon – Figure 1.3, page 9
* Aspirin (C9H8O4) - to relieve pain
* Use of TECHNOLOGY (benefit!)
6
Why Study Chemistry?
 Everyone
and everything around us
involves chemistry – explains our world
 What in the world isn’t Chemistry?
 Helps you make choices; helps make
you a better informed citizen
 A possible career for your future
 Used to attain a specific goal
 What did we describe as “pure” and
“applied” chemistry?
7
Why Study Chemistry?
 Figure
1.2, page 8
–What benefits do each of the
pictures represent in
improving our lives?
–Give examples in your daily
life that involve use of
chemistry, and things that do
not?
8
Section 1.2
Chemistry Far and Wide
 OBJECTIVES:
–Identify some areas of
research affected by
chemistry.
9
Section 1.2
Chemistry Far and Wide
 OBJECTIVES:
–Describe some examples
of research in chemistry.
10
Section 1.2
Chemistry Far and Wide
 OBJECTIVES:
–Distinguish between
macroscopic and
microscopic views.
11
Chemistry Far and Wide
 Chemists
design materials to fit
specific needs – velcro (Patented in 1955)
on page 12
 perfume, steel, ceramics, plastics,
rubber, paints, nonstick cooking
utensils, polyester fibers
 Two different ways to look at the
world: macroscopic and
microscopic
12
Chemistry Far and Wide
– we constantly have
greater demands
–We can conserve it; use wisely
–We can try to produce more; oil
from soybeans to make biodiesel
–fossil fuels, solar, batteries (that
store energy – rechargeable?),
nuclear (don’t forget pollution!)
 Energy
13
Chemistry Far and Wide
 Medicine
and Biotechnology–Supply materials doctors use to
treat patients
–vitamin C, penicillin, aspirin (C H O )
–materials for artery transplants
and hipbones
–bacteria producing insulin
9
14
8
4
Chemistry Far and Wide
 Agriculture
–Produce the world’s food supply
–Use chemistry for better
productivity – soil, water, weeds
–plant growth hormones
–ways to protect crops; insecticides
–disease resistant plants
15
Chemistry Far and Wide
 The
Environment
–both risks and benefits involved in
discoveries
–Pollutants need to be 1) identified
and 2) prevented
–Lead paint was prohibited in 1978;
Leaded gasoline? Drinking water?
–carbon dioxide, ozone, global
warming
16
- Page 16
Let’s examine some information from a graph.
88.2%
440,000
After lead was banned in gasoline and public water
supply systems, less lead entered the environment.
17
Chemistry Far and Wide
 The
Universe
–Need to gather data from afar,
and analyze matter brought back
to Earth
–composition of the planets
–analyze moon rocks
–planet atmospheres
–life on other planets?
18
Section 1.3
Thinking Like a Scientist
 OBJECTIVES:
–Describe how Lavoisier
transformed chemistry.
19
Section 1.3
Thinking Like a Scientist
 OBJECTIVES:
–Identify three steps in the
scientific method.
20
Section 1.3
Thinking Like a Scientist
 OBJECTIVES:
–Explain why collaboration
and communication are
important in science.
21
Alchemy – developed the tools and
techniques for working with chemicals
 The word chemistry comes from
alchemy – practiced in China and
India since 400 B.C.
 Alchemy has two sides:
–Practical: techniques for working
with metals, glass, dyes, etc.
–Mystical: concepts like perfection –
gold was a perfect metal
22
An Experimental Approach
 In
the 1500s, a shift started from
alchemy to science – King Charles
II was a supporter of the sciences
 “Royal Society of London for the
Promotion of Natural Knowledge”
 Encouraged scientists to use more
experimental evidence, and not
philosophical debates
23
Lavoisier
 In
the late 1700s, Antoine
Lavoisier helped transform
chemistry from a science of
observation to the science of
measurement – still used today
 He settled a long-standing debate
about burning, which was…
–Oxygen was required!
24
The Scientific Method
A
logical approach to solving
problems or answering questions.
 Starts with observation- noting and
recording information and facts
 hypothesis- a proposed
explanation for the observation;
must be tested by an experiment
25
Steps in the Scientific Method
1. Observations (uses your senses)
a) quantitative involves numbers = 95oF
b) qualitative is word description = hot
2. Formulating hypotheses (ideas)
- possible explanation for the
observation, or “educated” guess
3. Performing experiments (the test)
- gathers new information to help decide
whether the hypothesis is valid
26
Scientific Method




27
“controlled” experiment- designed to
test the hypothesis
only two possible answers:
1) hypothesis is right
2) hypothesis is wrong
We gather data and observations by
doing the experiment
Modify hypothesis - repeat the cycle
Scientific Method
We deal with variables, or factors that can
change. Two types:
1) Manipulated variable (or independent
variable) is the one that we change
2) Responding variable (or dependent
variable) is the one observed during the
experiment
 For results to be accepted, the experiment
needs to always produce the same result

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Outcomes over the long term…
29

Theory (Model)
- A set of well-tested hypotheses that give
an overall explanation of some natural
phenomenon – not able to be proved

Natural Law (or Scientific Law)
- The same observation applies to many
different systems; summarizes results
- an example would be:
the Law of Conservation of Mass
Law vs. Theory
A law
summarizes what has
happened.
A theory (model) is an
attempt to explain why it
happened – this changes as
new information is gathered.
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Using your senses to
obtain information
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Hypothesis is a
proposed explanation;
should be based on
previous knowledge; an
“educated” guess
The procedure that is used
to test the hypothesis
Tells what happened
A well-tested explanation for
the observations; cannot be
proven due to new discoveries
Collaboration / Communication
 When
scientists share ideas by
collaboration and communication,
they increase the likelihood of a
successful outcome
 Collaboration – Fig. 1.21, p. 24
 How is communication done?
 Is the Internet reliable information?
–http://www.dhmo.org
32
Section 1.4
Problem Solving in Chemistry
 OBJECTIVES:
–Identify two general steps
in problem solving.
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Section 1.4
Problem Solving in Chemistry
 OBJECTIVES:
–Describe three steps for
solving numeric problems.
34
Section 1.4
Problem Solving in Chemistry
 OBJECTIVES:
–Describe two steps for
solving conceptual
problems.
35
Problem Solving in Chemistry
 We
are faced with problems each
day, and not just in chemistry
 A solution (answer) needs to be found
 Trial and Error may work sometimes?
there is a method to problem
solving that works better, and these
are skills that no one is born knowing
– they need to be learned.
 But,
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Problem Solving in Chemistry


37
Effective problem solving usually
involves two general steps:
1) Developing a plan
2) Implementing that plan
The skills you use to solve a word
problem in chemistry are NOT
different from those techniques
used in shopping, cooking, or
planning a party.
Solving Numeric Problems
 Measurements
are an important part
of chemistry; thus many of our word
problems involve use of mathmatics
–Word problems are real life
problems, and sometimes more
information is presented than
needed for a solution
 Following skills presented will help
you become more successful
38
Solving Numeric Problems

The three steps we will use for
solving a numeric word problem are:
1) Analyze
2) Calculate
3) Evaluate

39
Let’s learn how
to ACE these
numeric word
problems!
The following slides tell the meaning
of these three steps in detail.
Solving Numeric Problems
1) Analyze: this is the starting point

40
– Determine what are the known factors,
and write them down on your paper!
– Determine what is the unknown. If it is
a number, determine the units needed
– Plan how to relate these factorschoose an equation; use table or graph
This is the heart of successful problem
solving techniques – it is the PLAN
Solving Numeric Problems
2) Calculate: perform the mathematics
– If your plan is correct, this is the
easiest step.
– Calculator used? Do it correctly!
– May involve rearranging an
equation algebraically; or, doing
some conversion of units to some
other units.
41
Solving Numeric Problems
3) Evaluate: – the finishing step
– Is it reasonable? Make sense?
Do an estimate for the answer,
and check your calculations.
– Need to round off the answer?
– Do you need scientific notation?
– Do you have the correct units?
– Did you answer the question?
42
Solving Conceptual Problems





43
Not all word problems in chemistry
involve doing calculations
Nonnumeric problems are called
conceptual problems – ask you to apply
concepts to a new situation
Steps are:
1) Analyze and 2) Solve
Plan needed to link known to unknown,
but no checking units or calculations
Do Conceptual Problem 2.1 on page 46
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