Chapter 1
“Introduction to
Chemistry”
Section 1.1
Chemistry
OBJECTIVES:
– Identify five traditional areas of study in
chemistry.
– Relate pure chemistry to applied chemistry.
– Identify reasons to study chemistry.
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.
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
Products
5 Major Areas of Chemistry
Analytical Chemistry- concerned with
the composition of substances.
Inorganic Chemistry- primarily deals
with substances without carbon
Organic Chemistry- essentially all
substances containing carbon
Biochemistry- Chemistry of living things
Physical Chemistry- describes the
behavior of chemicals (ex. stretching);
involves lots of math!
Boundaries not firm – they overlap and interact
- Page 8
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!)
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?
Why Study Chemistry?
Figure
1.2, page 8
–What benefits do each of the
pictures represent in
improving our lives?
–Give 3 examples in your daily
life that involve use of
chemistry, and 3 things that
do not?
Concept Check
1. Explain why chemistry affects all aspects of
life and most natural events.
2. Identify five traditional areas of study in
chemistry
3. Relate pure chemistry to applied chemistry.
4. Identify three reasons to study chemistry.
Section 2
Chemistry Far and Wide
OBJECTIVES:
– Identify some areas of research affected by
chemistry.
– Describe some examples of research in
chemistry.
– Distinguish between macroscopic and
microscopic views.
Materials
Chemists
design materials to fit
specific needs – velcro, perfume,
steel, ceramics, plastics, rubber,
paints, nonstick cooking utensils,
polyester fibers
Two different ways to look at the
world: macroscopic and
microscopic
Energy
We
constantly have greater
demands and chemistry helps to
meet those needs.
–We can conserve it; use wisely
»Example: Insulation
Energy
–Reduce the use of fossil fuels
»We can try to produce more; oil
from soybeans to make
biodiesel
–Find ways to store/produce
energy
»solar, batteries (that store
energy – rechargeable?),
nuclear (don’t forget pollution!)
Medicine and Biotechnology
Supply
materials doctors use to
treat patients
– Medicines are effective because they
interact with cellular chemistry.
–materials to repair/replace body
parts
»example: artery transplants
and hipbones
– Biotechnology applies science to
produce biological products
»Example: bacteria produce
insulin
Agriculture
Chemists
help tp develop more
productive crops and safer, more
effective ways to protect crops.
–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
»Genes from jellyfish
transferred to potato plant so
that it glows when it needs
watering.
The Environment
Chemists
identify pollutants and
prevent pollution.
– Pollutant: material that is harmful to
organisms
– both risks and benefits involved in
discoveries
The Environment
– Lead paint was prohibited in 1978;
Leaded gasoline? Drinking water?
»carbon dioxide, ozone, global
warming
- 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.
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?
Concept Check: Section 2
When
chemists develop new materials,
what is their general goal?
Name
three ways chemists help meet
the demand for energy.
How
do chemists help doctors treat
patients?
What
role do chemists play in
agriculture?
How
do chemists help to protect the
environment?
Describe
two ways chemists study the
universe?
Section 1.3
Thinking Like a Scientist
OBJECTIVES:
– Describe how Lavoisier transformed
chemistry.
– Identify three steps in the scientific method.
– Explain why collaboration and
communication are important in science.
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.
– Originally focused on turning items into gold.
Alchemy
has two sides:
– Practical: techniques for working
with metals, glass, dyes, etc.
– Mystical: concepts like perfection –
gold was a perfect metal
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
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!
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
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
Scientific Method
“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
Outcomes over the long term…
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.
- Page 22
Using your senses to
obtain information
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 – allows for different
knowledge or approaches to be used to
solve a problem.
Collaboration / Communication
How
is communication done?
Is the Internet reliable information?
– http://www.dhmo.org
Concept Check Section 3
What
did alchemists contribute to the
development of chemistry?
Describe
how Lavoisier transformed
chemistry.
Identify
three steps in the scientific
method.
Explain
why collaboration and
communication are important in science.
Section 1.4
Problem Solving in Chemistry
OBJECTIVES:
– Identify two general steps in problem
solving.
– Describe three steps for solving numeric
problems.
– Describe two steps for solving conceptual
problems.
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,
Problem Solving in Chemistry
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
Solving Numeric Problems
The three steps we will use for
solving a numeric word problem are:
– Analyze
– Calculate
– Evaluate
Let’s learn how
to ACE these
numeric word
problems!
Solving Numeric Problems
Analyze: this is the starting point
– 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
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.
Solving Numeric Problems
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?
Practice Problem
You
have to walk 8 blocks. How long will
it take if you can walk a mile in 20
minutes and 10 blocks equals 1 mile?
How
many blocks can be walked in 48
minutes?
How
many minutes does it take to walk 6
blocks and back?
Solving Conceptual Problems
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
Practice Problem
1. Describe 2 alternative orders in which
Manny could complete his errands.
2. What if Manny had 7 errands instead of
6? What would he need to do to adjust
for the extra errand?
Adapted from: Stephen L. Cotton, Charles
Page High School