“ Introduction to Chemistry”
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Transcript of “ Introduction to Chemistry”
“Introduction to Chemistry”
Chemistry
OBJECTIVES:–Identify five traditional areas of study in chemistry.
Chemistry
OBJECTIVES:–Relate pure chemistry to applied chemistry.
Chemistry
OBJECTIVES:–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 Chemistry1) Analytical Chemistry- concerned with
the composition of substances.2) Inorganic Chemistry- primarily deals
with substances without carbon3) Organic Chemistry- essentially all
substances containing carbon4) Biochemistry- Chemistry of living things5) 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?
Chemistry Far and Wide
OBJECTIVES:–Identify some areas of research affected by chemistry.
Chemistry Far and Wide
OBJECTIVES:–Describe some examples of research in chemistry.
Chemistry Far and Wide
OBJECTIVES:–Distinguish between macroscopic and microscopic views.
Chemistry Far and WideChemists 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
Chemistry Far and WideEnergy – 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!)
Chemistry Far and WideMedicine and Biotechnology-
–Supply materials doctors use to treat patients
–vitamin C, penicillin, aspirin (C9H8O4)
–materials for artery transplants and hipbones
–bacteria producing insulin
Chemistry Far and WideAgriculture
–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
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
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88.2%
440,000
After lead was banned in gasoline and public water supply systems, less lead entered the environment.
Let’s examine some information from a graph.
Chemistry Far and WideThe 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?
Thinking Like a Scientist
OBJECTIVES:–Describe how Lavoisier transformed chemistry.
Thinking Like a Scientist
OBJECTIVES:–Identify three steps in the scientific method.
Thinking Like a Scientist
OBJECTIVES:–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.
Alchemy has two sides:–Practical: techniques for working
with metals, glass, dyes, etc.–Mystical: concepts like perfection –
gold was a perfect metal
An Experimental ApproachIn 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
LavoisierIn 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 MethodA logical approach to solving
problems or answering questions.Starts with observation- noting and
recording information and factshypothesis- a proposed
explanation for the observation; must be tested by an experiment
Steps in the Scientific Method1. 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 right2) 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 change2) 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.
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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
A well-tested explanation for the observations; cannot be proven due to new discoveries
Tells what happened
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
Problem Solving in Chemistry
OBJECTIVES:–Identify two general steps in problem solving.
Problem Solving in Chemistry
OBJECTIVES:–Describe three steps for solving numeric problems.
Problem Solving in Chemistry
OBJECTIVES:–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? But, 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.
Problem Solving in Chemistry Effective problem solving usually
involves two general steps:1) Developing a plan2) 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:
1) Analyze2) Calculate3) Evaluate
The following slides tell the meaning of these three steps in detail.
Let’s learn how to ACE these numeric word problems!
Solving Numeric Problems1) 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 factors- choose an equation; use table or graph
This is the heart of successful problem solving techniques – it is the PLAN
Solving Numeric Problems2) 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 Problems3) 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?
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