Chapter 1

Living in a World of Chemistry

Living in a World of Chemistry

Chemistry is the study of matter and changes it undergoes.

Everything that we do involves chemistry

Chemistry : a central scienceChemistry is a central science. It is involved in

all we do.

Chemistry : a central science

Science is the process of seeking an understanding of underlying principles of nature. It involves two facets: technological (or factual), and philosophical (or theoretical).

Technology is the direct application of knowledge to solve problems.

Science grew out of natural philosophy or the philosophical speculation of nature.

Scientific Investigations• Science is the systematic exploration of

nature followed by a logical explanation of the observations.

• Scientific investigation entails:– planning an investigation– carefully recording observations– gathering data– analyzing the results

The essential steps of Scientific Method are summarized in the next slide

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Scientific MethodHypothesis The initial ,tentative proposal of a scientific principle.

Experiment:Experiments are then designed to test the hypothesisIf the experimental data supports the initial proposal, the hypothesis may lead to a scientific theory.

Scientific Methodscientific theory.An explanation that is based on observation, experimentation & reasoning and has been tested several times.

scientific LawA measurable relationship that summarizes the natural behavior.

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Scientific MethodExample 1A scientific hypothesis is

a) absolute.b) complex.c) simple.d) Tentative

Scientific Method

Example 2What is a scientific theory?

a) It is a collection of experimental data.b)It is an assertion of scientific fact.c) It is a speculation about the natural phenomena.d)It is an explanation of natural phenomena that

has undergone significant testing.

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Scientific MethodExample 3

A brief statement summarizing many observations of a physical phenomenon is called a

a) scientific theory. b) hypothesis. c) fact. d) scientific law

Baconian Dream and Carsonian Nightmare

• It was the dream of Francis Bacon (philosopher) that science would solve the world’s problems and enrich human life with new inventions, thereby increasing happiness and prosperity

Baconian Dream and Carsonian Nightmare

• Rachel Carson (biologist) published Silent Spring in 1962.

• She proposed that the use of chemicals to control insects was threatening the destruction of all life.

Ozone Layer

Ozone hole & CFC’S

Ozone hole & CFC’S

Ozone hole & CFC’S

Ozone hole & CFC’S

Ozone hole & CFC’S

Ozone hole & CFC’S

Global Warming

Global Warming• Scientists have measured an average 0.6 °C rise in

atmospheric temperature since 1860

• During the same period atmospheric CO2 levels have risen 25%

• Are the two trends causal?

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Green House

The Sources of Increased CO2• One source of CO2 is the combustion reactions of fossil fuels

we use to get energy• Another source of CO2 is volcanic action• How can we judge whether global warming is natural or due

to our use of fossil fuels?

25Tro: Chemistry: A Molecular Approach, 2/e

Global Warming & Fossil Fuels

Global Warming & Green house Effect

Risk-benefit analysis

Science and technology are interrelated. They involve both risks and benefits.

Risk-benefit analysis involves an estimation called the desirability quotient (DQ).

DQ = BenefitsRisks

Basic & Applied Science

Basic research involves the search for knowledge for its own sake.

The findings of basic research can someday be applied to a specific problem in industry or the environment.

Basic & Applied Science/Research

Applied research involves studying a specific problem in the industry or the environment.

George Washington Carver’s work with peanuts was an example of applied research. In doing so, he developed more than 300 products from peanuts.

DNA: Heriditary material

• DNA analysis has played an important role in ‘Forensic science”

• Helped understanding heriditary diseases .

• Helped develop drugs to cure these diseases

• Developing Gene Therapy

DNA: Double Helix

DNA: Double Helix

ExampleWatson and Crick proposed that DNA exists as a(n)A) alpha helix.B) double helix.C) beta sheet.D) pleated sheet

Your Attitude toward Chemistry• Different people learn

chemistry differently.

• What do you see in the picture?

• Some people see a vase on a dark background; some people see two faces.

• How do you look at chemistry?