Chapter 1“Introduction to

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

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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!)

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 examples in your daily life that involve use of chemistry, and things that do not?

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?Section 1.3

Thinking Like a Scientist

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 = 95oFb) 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.

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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 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 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:

1) Analyze

2) Calculate

3) 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

Do Conceptual Problem 2.1 on page 46