Chapter 1

Chemistry: A Science for All Seasons

I. What is Science?

A. What are the characteristics of SCIENCE?

B. What is TECHNOLOGY? Is it science?

C. What is PHILOSOPHY? Is it Science?

Technology

Technology = factual• Use of scientific facts

to do work or accomplish a goal without understanding WHY an event occurs or how something works

• Examples:• using fire to cook• Fermentation of juice

to wine• Others?

Philosophy

Philosophy = theoretical explanation of WHY something occurs

• Began with Greeks – developed theories,

– but did not TEST them

• Middle ages: Alchemy– Some experimentation

in medicine

– Tried to change metals to gold, attain immortality

– Technology was too limited!

Philosophy- cont’d

• Renaissance: “Natural Philosophy”– Thinking about

“nature”

– Technology more advanced

– Began to question WHY and not simply accept on “faith”

• Invention of printing press– More people became

education

– Greater ability to think and ask WHY

Philosophy- cont’d

• 1700s –1800s– Technology advancing

– More open minds

– “science” still not a “profession”

• Began true careful experimentation– Many simple but

elegant experiments to determine the nature of matter

Web references from text

• History of chemistry

http://webserver.lemoyne.edu/faculty/giunta/papers.html

http://echo.gmu.edu/center/

So What is Science?

• An accumulation of knowledge about Nature and the physical world

• BASED ON OBSERVATIONS

5 Characteristics of Science

• Testable: ask questions and devise experiments• Reproducible: others should get same results when

repeating your experiment• Explanatory: explain WHY something is as it is,

in a TESTABLE manner• Predictive: based on past experience, predict what

will happen (if…then..)• Tentative: explanations able to be modified in

light of new data

Scientific Method• Logical format to solve problems• 4 parts:

– Make observations: look at what is happening, then ask a question: Does X effect Y?

– State a hypothesis: what you think will happen based on trends in observations: If X, then Y will soon follow

– Do an Experiment: Do X. What happens?– Make Observations: Is Y occurring?

• If yes, hypothesis OK; • If no, then go back and reformulate hypothesis

49

50

• Use the Scientific Method to make discoveries, establish hypotheses

• Leads to development of MODELS– Help us visualize a process based on numerous

hypothesis and experimental outcomes– Tangible items or pictures to represent invisible

processes– Help us understand something

The Scientific Approach to Problem Solving

The Scientific Approach to Problem Solving

Scientific Theories– Detailed explanations of WHY– Represent best possible explanation given

current understanding and technology– Are VERY TENTATIVE

The Scientific Approach to Problem Solving

Scientific Laws– Brief, overall summaries about nature– Are “UNIVERSAL”- hold true in stated

conditions tested, everywhere in the universe

The Scientific Approach to Problem Solving

• Requires CREATIVITY– To develop multiple, testable hypotheses– To develop models– To envision HOW and WHY something is the

way it is!

Tutorial: The Scientific Method

http://antoine.frostburg.edu/chem/senese/101/intro/scimethod-quiz.shtml

Limitations to Science

• We cannot control ALL variables in many experiments– Example: influence of amounts of fats in diet

on heart disease• Data collected over many years from many people

in many countries---- suggests an association between fat in the diet and heart disease

• Can’t really do a fully controlled experiment on people (take 1000 identical people from birth to death, give same diet and living conditions, etc)

Limitations to Science

• Can do some tests in animals, but still NOT the same

• BE CAREFUL with how scientific conclusions are offered to the public– it may or may not be relevant!

• Science is NOT the “all-knowing, all-powerful” entity as many seem to think it is!

• Current knowledge is LIMITED• Don’t have all the answers!!!!

How is Society Provided with Scientific Advancements?

“Applied” Research-– Work oriented toward solution of a specific

problem– Has a specific goal

• Design a drug to lower blood pressure

• Build a car to run on renewable fuels that does not create much pollution

How is Society Provided with Scientific Advancements?

“Basic”Research– Aim is to find out WHY, for the sake of simply

knowing!– Not directly linked to the development of a

product or technology– No immediate benefit, other than satisfying

curiosity– Is the basis of future applied research

Importance of Basic Research

“There are two compelling reasons why society must support basic research.One is substantial: the theoretical physics of yesterday is the nuclear defense of today; the obscure synthetic chemistry of yesterday is curing disease today. The other reason is cultural. The essence of our civilization is to explore and analyze the nature of man and his surroundings.As proclaimed in the Bible in the Book of Proverbs: Where there is no vision, people perish.”

Arthur Kornberg, 1959 Nobel Prize winner

57

How Does Society Make Decisions to Accept/Reject Scientific

Advancements?• Technology – its risks and benefits.

– Technology defined = human modification of the materials of nature to satisfy needs and wants.

– There can always be risks associated with technological advancements.

• Benefits from technology must be analyzed against its possible risks.– Risk-benefit analysis – desirability quotient (DQ_ =

benefits/risks.– Examples?

• Stem cell research.

58

How Does Society Make Decisions to Accept/Reject Scientific

Advancements?

• Critical thinking = how to test a claim (FLaReS tests).– Falsifiability = things not proven false may be

accepted as truth, but later may be modified.– Logic = it is unsound if the premise is falseand

if there is a single exception to the premise.– Replicability = it is necessary that the results

can be repeated without deviation.– Sufficiency = evidence must be adequate to

establish the truth of the claim.

Risk Assessment Assignment:

• Get into groups of 4– Read assigned article– Think about the article, gather additional info

(web, newspapers, books, etc)– Meet outside of class to to discuss article with

each other and prepare brief overview of issue, pros and cons; RISK ASSESSMENT

– NEXT CLASS MEETING: Present to CLASS

So Why Study Chemistry?

• To be better informed

• To be a knowledgeable consumer

• To make better decisions for yourself and society

• To learn problem-solving skills

• To enhance analytical thinking

Chemistry as the “Central Science”

• Chemistry = the study of matter and the transformation it undergoes

• EVERYTHING is a CHEMICAL– Table salt = sodium chloride, NaCl

– Table sugar = sucrose, C12H22O11

– Clothes: Wool? Cotton? Polyester?

– Body: lipids, Proteins, Carbohydrates, DNA/RNA

– You name it– it’s a chemical!

Chemistry as the “Central Science”

• Chemistry is the driving force behind many “liberal arts”– Composition of paints? Colors?

– Economies of industrial nations• #1 commercial chemical is sulfuric acid– LOTS of uses!

• All idustry involves chemical processes

– Economies of Developing Nations• Agriculture depends on chemicals as fertilizers, pesticides

– Politics and Natural Resources

Assignment: Chemistry in your major

• Find a current news story or historical example that demonstrates the importance of chemistry to your major– For example: chemical resource as a key issue

in a political / economic rift; wars fought over chemical resources; etc

• Write a 2 paragraph summary on issue and its relevance to your studies

Chemistry as the “Central Science”

Chemistry

• Definition = the study of matter and the changes it undergoes

• Matter = the stuff that makes up everything; anything that has mass– Mass = the quantity of matter a mass contains– Weight = a measure of the force of gravity

upon a specific mass

Properties of Matter

Physical Properties = characteristics of a material

Color MassTemperature OdorDensity HardnessSolubilityConductivity (heat or

electrical)Freezing/boiling point

Chemical Properties = describe how a material reacts with another type of matter

Ability to burn

Ability to rust / corrode

Ability to make a solution acidic or basic

Lack of ability to react with something

Changes in MatterPhysical Changes = a

change in a physical property; does NOT change the chemical composition or atomic arrangement of the material– Increase in temperature

– Phase changes

– Cutting into smaller pieces

Chemical Changes = changes that alter the identity of a material, a change in the chemical composition or atomic arrangement of the material– Wood burns in air to

produce CO2 and H2O– Cooking an egg (change

molecular structure of the proteins, loss of water)

– Formation of rust (iron to iron oxide)

Classification of Matter4 Phases: solid, liquid, gas, plasma

Solid:Fixed shape and fixed volume;

Atoms tightly packed together

Classification of Matter

Liquid:No fixed shape but maintains a fixed volume

Atoms loosely packed together, slide around each other

Classification of Matter

Gas:No fixed shape or volume

Atoms not really associated with neighbors at all

Classification of Matter

Plasma:

mix of subatomic particles with not organization

(sun)

Classification of Matter

Substances vs Mixtures

Substance – has a definite or fixed

composition

– Composition does not vary from sample to sample

Mixture– Has a varied

composition

– Each individual component can be separated by physical means

– Ex: salt and pepper, sugar in water, sea water

Mixtures:Homogeneous • Same composition

throughout sample• Ex- milk, tea, others?

Heterogeneous• Different samples of

the same mixture have different compositions

• Ex- air in the room others?

SubstancesElements• Fundamental

substances from which all things are constructed

• Only one type of atom is present

• Can not be broken down any further

SubstancesCompounds• Substances made up of

two or more elements in distinct ratios

• Molecules: smallest characteristic part of a compound; composed of a distinct and unique arrangement of elements

Tutorial: Classifying matter

http://antoine.frostburg.edu/chem/senese/101/matter/classify-matter-quiz.shtml

Elements

Elements- KNOW these names and symbols!!

Hydrogen H Helium HeLithium Li Berylium BeBoron B Carbon CNitrogen N Oxygen OFluorine F Neon NeSodium Na Magnesium MgAluminum Al Silicon SiPhosphorous P Sulfur SChlorineCl Argon Ar

Elements- KNOW these names and symbols!!

Potassium K Calcium Ca

Scandium Sc Titanium Ti

Vanadium V Chromium Cr

Manganese Mn Iron Fe

Nickel Ni Copper Cu

Zinc Zn Gallium Ga

Germanium Ge Arsnic As

Selenium Se Bromine Br

Elements- KNOW these names and symbols!!

Silver Ag Gold Au

Iodine I Lead Pb

BariumBa Uranium U

Plutonium Pu Thorium Th

Bismuth Bi Mercury Hg

(and any others I mention later!)

Element tutorials

http://www.uky.edu/Projects/Chemcomics/

http://chemicalelements.com/

http://www.chem4kids.com/

http://www.webelements.com/

http://pearl1.lanl.gov/periodic/default.htm

Compounds

• Substances made up of two or more elements in distinct ratios

• Exist as molecules– Smallest characteristic part of a compound– composed of a group of atoms arranged and

connected in a definite and specific way

Compounds

• If the ratio of elements or the order of connections changes, then the identity (and physical and chemical properties) of the material changes– CO vs CO2

vs

Analogy

• Chemistry is a language:

• The elements are letters;

• The compounds are words;

• Chemical reactions are sentences.

Measurement of Matter Science is based on OBSERVATIONS

Qualitative • Describes a property

or function• Answers “what is it

like?”• Useful for identifying,

describing, organizing, and categorizing

Quantitative• A number; tells how

many • A measurement must

have a number and a UNIT –something to qualify the number

International System of Units

Physical quantity

Name of unit Symbol

length meter m

mass gram g

time second s

temperature Kelvin K

amount mole mol

energy joule J

Metric Prefixes

Metric Prefixes-cont’d

Meaning of 1000

10 cm

10 cm

10 cm 103 cm3 =

1000 cm3 =

1 L

1 cm

1 cm1 cm

1 cm3 = 1 mL

Scientific Notation

Scientific Notation

Scientific Notation

Scientific Notation-Examples

6 6 6 X 100

60 6 * 10 6 X 101

600 6 * 10 * 10 6 X 102

6000 6 * 10 * 10 * 10 6 X 103

Scientific Notation-Examples

6.4 6.4 6.4 X 100

64 6.4 * 10 6.4 X 101

640 6.4 * 10 * 10 6.4 X 102

6400 6.4 * 10 * 10 * 10 6.4 X 103

Scientific Notation-Examples

6.02 6.02 6.02 X 100

60.2 6.02 * 10 6.02 X 101

602 6.02 * 10 * 10 6.02 X 102

6020 6.02 * 10 * 10 * 10 6.02 X 103

60,200 6.02 * 10 * 10 * 10 * 10 6.02 X 104

620,000 6.02 * 10 * 10 * 10 * 10 * 10 6.02 X 105

Scientific Notation

Metric Prefixes “Game”1 femto-bismol

1 picoboo

1 boo boo

1 attoboy

1 terabull

1 decacards

1 nanogoat

1 milliking machine

1 gigalo

10-15 bismols

10-12 boos

1 boo2

10-18 boys

1012 bulls

101 cards

10-9 goats

10-3 king machines

109 los

Metric Prefixes “Game”1 decimate

1 megaphone

1 terapin

1 microphone

1 centimental

1 centipede

1 petafile

10-1 mate

106 phones

1012 pins

10-6 phones

10-2 mentals

10-2 pedes

1015 files

Metric Prefixes – cont’d

• Use metric prefixes to get rid of exponentioal notation

• BE ABLE to convert between units978 g = 0.978 kg

13,096 um = 13.096 m

Factor-Label Method

• Logical way to convert units• 6 step process = make a bridge!

1. Identify starting amount and number2. Identify “Goal” units3. List conversion factors4. Set up grid and fill in5. Be sure all labels cancel!6. Do the math!

What are conversion factors?

• A fixed ratio between two quantities

1 mole of gas at STP has a volume of 22.4 liters.

•An equation written on its side

3 feet = 1 yard

•Always two possible conversion factors

3 feet = 1 yard

1 yard 3 feet

HOLY MOL-EE! Sing-Along Chemistry T-28. Conversion Factor Discussion Slide

Copyright 2000 Lynda J. Jones www.sing-smart.com

Factor Label Grid

Place conversion factors in grid such that the units cancel!

=

=

=

=

Conversion

factors

Conversion SheetCH 131 Fall 2002

Length Mass Volume

1 in = 2.54 cm 1 lb = 454 g 1 qt = 946 mL

39.4 in = 1 m 2.20 lbs = 1 kg 1.06 qt = 1 L

0.621 mi = 1 km 1 oz = 28.5 g 0.034 fl oz = 1 mL

1 mL = 1 cm 3

Pressure Energy Temperature

1 torr = 1 mm Hg 4.184 J = 1 calorie oF = (9/5)oC +32

1 atm = 760 mm Hg 1 kcal = 1 “food”cal K = oC +273

1 atm = 101.3 kPa

Example problemHow many kg does a 140 pound person weigh? • 6 step process

1. Identify starting amount and number (140 lbs)

2. Identify “Goal” units (kg)

3. List conversion factors (2.20 lbs = 1 kg)

4. Set up grid and fill in

5. Be sure all labels cancel!

6. Do the math!

140 lbs

2.20 lbs

1 kg = 63.6 kg

More problems…

A recipe calls for 3.0 g of baking soda. Given that 1 tsp has a mass of 0.1 ounce, how many teaspoons of baking soda will you need?

More problems…

Professor X is moving from one office to another. He has accumulated 1249 books over his career. Assuming each book weighs 5.0 lbs (on average), how many boxes will be need? Each box can hold 100 kg.

More problems…

I want to build a split rail fence around part of my yard. The front and back boarders are 200 feet long each; each side is 300 feet long. How much will this cost, given that I need two rails for every 8 feet and 1 pole every 8 feet, and that rails cost $5.50 each and poles cost $ 13.75 each?

Dimension Analysis Worksheet

• Handout worksheet

• Due on Sept. X

• WORK INDIVIDUALLY

Length vs. Area vs. Volume

Length = 1 dimension

2 m

Area = 2 dimensions

2m * 2 m = 4 m2

Volume = 3 dimensions

2m * 2m * 2m = 8 m3

2 m

2 m

2 m

2 m

2 m

2 m

Length vs. Area vs. Volume

• Be careful! When using 2- and 3-dimensional units, you must account for each!

• THINK: 3 cm3 = 3 cm*cm*cm

Density

- the mass contained by an object of a given volume

Density = mass volume

- measurement of how closely the atoms are packed in a material

- the more closely packed, the greater the density

4 Factors effecting Density

1. Density of individual atoms

ex- Al vs Pb

2. Atomic Packing

ex- foam pieces fitting into a container

3. Temperature

ex- hot air balloon

4. Pressure

ex- shaving foam inside vs. outside can

Density Calculations

What is the density of a liquid if 240 ml has a mass of 690 g?

D = m = 690 g = 2.88 g/mL

V 240 mL

Density Calculations

What is the mass of a 1.6 cm * 4.9 cm * 10.3 cm block of wood, given a denisty of 0.93 g/cm3?

D = m so m = D * V V

V = 1.6cm*4.9cm*10.3cm = 80.7 cm3

m = 0.93 g * 80.7 cm3 = 75 g cm3

Energy

Energy in matter is either given off or absorbed during physical or chemical changes

Source = ultimately, the sun

captured energy by plants (photosynthesis) = fossil fuels

coal, petroleum, natural gas

Energy Sources

2 Forms of Energy

Potential Energy• Stored energy;• Energy of position• Ex- ball on top of ahill• Ex- Energy “within”

chemical bonds

Kinetic Energy• Energy of motion• Ex- ball rolling down

a hill• Ex- energy released or

put into a reaction to make it go

Heat vs. Temperature

Heat

• A form of energy;

• The amount of energy (potential or kinetic) an object possesses

• Flow of energy from a “warm” to “cold” body

Temperature

• Measure of the amount of heat energy

• Something “hot” has more energy than your hand– feel heat energy flowing to your hand

• Something “cold” has less Heat energy-feel heat flowing from your hand!

Heat

SI Unit = Joule (J)1 calorie = 4.184 J = amount of heat needed to raise

the temperature of 1 g of water by 1oC1 food calorie = 1000 caloriesSo…1 banana split = 1500 food calories

= 1,500,000 calories = increase temp of 1500 kg of

water by 1 oC!

Temperature

• Three scales: Fahrenheit , Celcius/centigrade, and Kelvin

• Be able to convert from one scale to another!

oF = (9/5)oC + 32

K = oC +273

Temperature Scales

Chapter 1 Learning Objectives1. Be able to define and differentiate between the following terms:

Chemistrymatter mass science hypothesis

universal theories predictive models

Variables Scientific laws

2. Be familiar with the 5 characteristics of science: testable, reproducible, explanatory, predictive, and tentative.

 3. Know that science has limits; what are the limits? Why? 

4. Differentiate between science and technology.

• 5. Define Risk Analysis; understand how, as a society, we must weigh the benefits of a technology against the risks associated with it. What is a desirability quotient (DQ)? Why study chemistry, with respect to risk analysis?

• 6. Understand why chemistry is often referred to as the “central science”.

• 7. Differentiate between applied and basic research; know, however, how they are interrelated.

• 8. Differentiate between mass and weight.

• 9. Differentiate between chemical and physical properties. Name three examples of each.

• 10. Differentiate between chemical and physical changes. Name three examples of each.

 

• 11. Understand the different ways to classify matter:• a.)   Know the three regular phases of matter (solids, liquids,

and gases) and the defining properties of each.• b.)   Differentiate between substances and mixtures; sub-

classify substances as elements or compounds and sub-classify mixtures as homogeneous or heterogeneous.

• c.)    Differentiate between atoms and molecules.

• 12. Know the names, symbols, and location in the periodic table of the elements listed in table 1.3 of the text.

 • 13. Know the seven S.I. base units for measurements (table

1.4). • 14. Know the metric prefixes (table 1.5) and what they

represent. Be able to interconvert between metric units; be able to convert metric units to English units (and vice versa) using dimensional analysis.

 

• 15. Be able to use exponents (powers of 10, scientific notation) to interconvert metric units.

 • 16. Be able to use dimensional analysis to solve unit-related

problems. • 17. Understand what density is and how to use it as a

conversion factor in dimensional analysis problems. • 18. Define energy; understand that chemical changes often are

accompanied by changes in energy that can be harnessed for useful work. Differentiate between potential and kinetic energy (see table 1.8). Understand that there are different forms of potential energy and that energy can be converted from one form to another.

 • 19. Differentiate between heat and temperature. Know the

units for temperature (K, oC, oF) and be able to interconvert between units. Know the units for heat (J and cal) and be able to interconvert between units.