Chapter 1Chapter 1““Introduction to Chemistry”Introduction to Chemistry”

Pequannock Township High SchoolChemistry

Mrs. Munoz

Section 1.1Section 1.1ChemistryChemistryOBJECTIVES:

◦Identify five traditional areas of study in chemistry.

◦Relate pure chemistry to applied chemistry.

◦Identify reasons to study chemistry.

What is Chemistry?What is Chemistry?

Chemistry is the study of the composition of “matter”

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.

The chemistry is shown as a chemical equation (reaction equation):

C2H5OH + 3 O2 2 CO2 + 3 H2O + Energy

Reactants Products

5 Major Areas of Chemistry5 Major Areas of Chemistry1) Analytical Chemistry: concerned with

the composition of substances2) 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 of the areas of chemistry overlap and interact.

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What is Chemistry?What is Chemistry?

Pure chemistry: gathers knowledge for the sake of knowledge

Applied Chemistry: uses chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing. Applied chemistry leads to an application* Nylon – Figure 1.3, page 9* Aspirin (C9H8O4) - to relieve pain

Why Study Chemistry?Why Study Chemistry?Everyone and everything around us involves chemistry – explains our world

Helps you make choicesHelps make you a better informed citizen

A possible career for your futureUsed to attain a specific goal(What did we describe as “pure” and “applied” chemistry?)

Section 1.2Section 1.2Chemistry Far and WideChemistry Far and WideOBJECTIVES:

◦Identify some areas of research affected by chemistry.

◦Describe some examples of research in chemistry.

◦Distinguish between macroscopic and microscopic views.

Chemistry Far and WideChemistry Far and WideChemists design materials to fit specific needs – velcro (page 12)

Examples of chemistry: 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 WideChemistry 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 WideChemistry Far and Wide

Medicine and Biotechnology-oSupply materials doctors use to treat patientsovitamin C, penicillin, aspirin (C9H8O4)omaterials for artery transplants and hipbonesobacteria producing insulin

Chemistry Far and WideChemistry 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

Chemistry Far and WideChemistry Far and WideThe 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 WideChemistry 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 1.3Section 1.3Thinking Like a ScientistThinking Like a ScientistOBJECTIVES:

◦Describe how Lavoisier transformed chemistry.

◦Identify three steps in the scientific method.

◦Explain why collaboration and communication are important in science.

AlchemyAlchemy – developed the – developed the tools tools and techniquesand techniques for working with for working with chemicalschemicals

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 ApproachAn 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

LavoisierLavoisier

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 MethodThe 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 MethodSteps in the Scientific Method

1. 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” guess3. Performing experiments (the test)

- gathers new information to help decide whether the hypothesis is valid

Scientific MethodScientific 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 MethodScientific 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…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. TheoryLaw vs. Theory

A A lawlaw summarizes summarizes whatwhat has has happened.happened.

A A theorytheory (model) is an (model) is an attempt to explain attempt to explain whywhy it it happened – this changes as happened – this changes as new information is gathered.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 / CommunicationCollaboration / 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?

Section 1.4Section 1.4Problem Solving in Problem Solving in ChemistryChemistryOBJECTIVES:

◦Identify two general steps in problem solving.

◦Describe three steps for solving numeric problems.

◦Describe two steps for solving conceptual problems.

Problem Solving in ChemistryProblem Solving in ChemistryProblems exist 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. Problem solving skills need to be learned.

Problem Solving in ChemistryProblem 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 ProblemsSolving Numeric Problems

Measurements are an important part of chemistry. Many chemistry word problems involve use of mathematics.

Word problems are real life problems, and sometimes more information is presented than needed for a solution.

The following skills presented will help you become more successful.

Solving Numeric ProblemsSolving 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 Problems, Step 1Solving Numeric Problems, Step 1

1) 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 problemsolving techniques – it is the PLAN!

Solving Numeric Problems, Step 2Solving Numeric Problems, Step 2

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.

Solving Numeric Problems, Step 3Solving Numeric Problems, Step 3

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?

Solving Conceptual ProblemsSolving Conceptual Problems

Not all word problems in chemistry involve numerical/definitive calculations

Nonnumeric problems are called conceptual problems – just apply concepts to a new situation

Steps are:1) Analyze2) Solve

Plan needed to link known to unknown, but no checking units or calculations