Science and Technology: The Roots of Knowledge

SCIENCE AND TECHNOLOGY: THE ROOTS OF KNOWLEDGE

Chemistry is a science, but what is science? Lets examine the roots of science. Our study of the material universe has two facets: The Technological (factual) and Philosophical ( theoretical).

What is science if scientists dispute what is and what will be? Is science merely a guessing game in which one guess is as good as another? We cannot defined science precisely. Rather, we must resort to describing it.

a. Scientific Hypotheses
- One essential characteristics of science is that its tenets are testable. Scientists make hypotheses that can be tested by experiment.

b. Scientific Laws
- large amounts of scientific data can sometimes be summarized in brief statements called scientific laws.

c. Scientific Theories
- Science is a way of explaining nature, but the explanations have to be tested against a sometimes less-than-agreeable nature.
- Science is a body of knowledge, but the knowledge is always tentative, scientists use detailed explanations, called theories, as a framework for the organization of scientific knowledge. These theories represent the best explanations of phenomena based on current knowledge. Sometimes a theory has to be modified or discarded in the light of new observation.
- Theories are useful mainly for their predictively value.

d. Scientific Models
- Scientists often use models to help explain complicated phenomena. Scientific models use tangible items and pictures to represent invisible processes.

What is science, then? We can only state some of its characteristics: it is testable, explanatory, and tentative. Contrary to popular notion, scientific knowledge is not absolute, Science is cumulative, but the body of knowledge is growing , changing, and never final. New facts and new concepts are always being added. Old concepts, or even old facts. Are discarded when new tools, new questions, and new techniques reveal new data and generate new concepts.

SCIENCE
- is the study of an accumulated and accepted knowledge, which has been systematized and formulated to serve as the basic for the discovery of general truths. Come from a Latin word “ SCIRE” ( to know).

Science and Technology
-Science and Technology are interrelated. In everyday life, people often fail to distinguish. Technology is the sum total of the processes by which humans modify the materials of nature to better satisfy their needs and wants.
SCIENTIFIC METHOD
-consist of the observation and classification of facts, based on experimental evidence. These observations are correlated into a tentative theory called hypothesis, this is often used tested further and if found to be correct a scientific law is proposed which gives a statement of the behavior of nature.

CHEMISTRY AS A BRANCH OF SCIENCE

- Chemistry is a branch of natural science, Natural science is an organized body of knowledge based on the observations of physical facts and is limited to man’s physical experience.

CHEMISTRY
- Study of the composition , structure, properties and interactions of matter.
- Study of matter and the changes it undergoes.

HISTORY
- Chemistry rose from attempts by people to transform metals into gold beginning about AD 100, an effort that become known as ALCHEMY.

A. PREHISTORIC MAN
- used metals/ made of pottery and bricks.
- cooked food, smelted ores to produce metals such as copper. They made beer and wine for fermentation, and obtained dyes and drugs from plants and materials. These things and many others- were accomplished without understanding of the scientific principles involved.

B. 400 BC
- Beginning of chemistry as a science; the four element theory
( Earth, Wind, Fire and Water), ( Dry, Hot ,Cold and Wet).

C. FIRST CENTURY
- Combinations of the arts of the Egyptians and the Greeks,
- The Greek Philosophers, about 2,500 years were perhaps the first to formulate theories by explaining the behavior of matter.
- The term Chemistry meant “ EGYPTIANS ART”
- The first book of Chemistry as a Science written in Egypt.
- Also the beginning of ALCHEMY in China.

D. 12TH CENTURY
- Alchemy reached Europe through Spain, they interest in human and quality of life.

E. 16TH AND 17TH CENTURY
- Chemistry applied to medicine, the study of gases begun, quantities/ qualities experiments begun.
- Science had its true beginnings in the seventeenth century, when astronomers, physicists and physiologist began to rely on experimentation.
- First textbook of Chemistry written 1597.
- Boyle studied gases and criticized the basic areas of Alchemy in his book
“The Skeptical Chemist”

F. 18TH CENTURY
- Phlogiston theory proposed: Oxygen discovered 1774, careful quantities work by LAVOSIER.
- Modern Chemistry was established in the late 18th century as scientist began identifying and verifying through scientific experimentation, the elemental processes and interactions that create the gases, liquids and solids.

G. 19TH AND 20TH CENTURY
- chemists learned how to create new substances that have many important applications in our lives.
- Everyday applications of Chemistry chemical reactions occur continuously in the atmosphere, in factories, in vehicles, in the environment and in our bodies.
- In a chemical reaction, one or more kinds of matter is changed into a new kind- or several new kinds of matter.
-life as we know it could not exist without these processes; plants could not photosynthesize, cars could not move, muscles could not burn energy, glue could not stick and fire could not be burn.

BRANCHES OF CHEMISTRY

A. INORGANIC CHEMISTRY
-is the study of the chemical nature of the elements and their compounds.
B. ORGANIC CHEMISTRY
- is the study of compounds consisting largely of hydrocarbons ( form rings)
-form coal and petroleum, chemistry have learned how to convert raw materials, drugs, plastics and many other products.
C. RADIOCHEMISTRY
-study of chemical effects on high-energy radiation and the behavior of radioactive isotopes, atoms of the same elements
- as the atoms breaks apart, energy is release in the form of electromagnetic waves and electrically charged bits of matter. This energy is called RADIATION.
D. PHYSICAL CHEMISTRY
- is fundamental to all chemistry and deals with the applications of physical laws to chemical system and chemical change.
- it is also concerned with the role of energy in chemical reactions
- Thermodynamics ( branch of physical chemistry)
- Chemical Kinetics ( the rate and mechanism reaction)
- Quantum Theory – study molecular structure by examining the spectrum of electromagnetic energy emitted by molecules and explained structure using the quantum principles.
Subfields:
a. Electrochemistry ( electric current)
b. Colloid Chemistry ( behavior of finely particles of matter)
c. Surface Chemistry ( deals with nature of surfaces and absorption photochemistry)
d. Statistical Chemistry ( which applies the laws of probability to large numbers of particles).

E. ANALYTICAL CHEMISTRY
- is the science of separating complex materials into simpler one and detecting and measuring the constituents.
- the oldest branch of chemistry.

2 Division

a. Qualitative Analysis – determines what elements or compounds are present in a sample “WHAT”
b. Quantitative Analysis – determines the percentage, finds out “HOW MUCH” of those elements are present in a sample.

F. BIOCHEMISTRY
- is the chemistry of living organism and life processes ( respiratory, digestion, metabolism, growth and reproduction).
G. INDUSTRIAL CHEMISTRY
- Deals with the transformation of raw materials of nature into finished products.
H. GEOCHEMISTRY
- is the application of chemistry to processes taking place in the earth, such as mineral formation, the metamorphosis of racks.

AIMS

1. To study the different properties of matter as to distinguish them from one another.
2. To devise means and ways of separating one substances from another.
3. To find conditions necessary from promoting or preventing changes of matter.
4. To devise ways and means of consulting natural products into commodities necessary for the enjoyment and enrichment of human life.
5. To determine the amount of matter and energy involved in a given change.


SCIENTIFIC NOTATION
- to avoid writing too many zeros/shorthand method of writing.

N x 10 n
Ex. N- number between 1 to 10 1- 10
n - positive (+ ), negative (- )
RULES:

1. Find N by moving the decimal point so that you leave only one non-zero digit to the left of it.
2. Find n by counting the number of phases through which you moved the decimal point. If you move the decimal point to the left, n is positive (+), this means the number is greater than 1. If you move the decimal point through the right, n is negative, means the number is less than 1.

Ex: 1. 2.61 x 10 11 = 261,000,000,000
2. 6.84 x 10 -9 = .00000000684
3. 4.06 x 10 -7 = .000000406
4. 30,000,000,000 = 1 x 10 -8
5. 346,000,000 = 3.46 x 10 8
ADDITION AND SUBTRACTION
The key to adding or subtracting numbers in scientific notation is to make sure the exponents are the same. The problem needs to be written so that the exponent are the same.

Ex. A. ( 0.3 x 10 3 ) + ( 3.0 x 10 3 ) = 3.3 x 10 3
B. 2 x 10 2 + 3.0 x 10 3 = 3.2 x 10 3
200 + 300 = 3,200
C. ( 200 x 10 5) – ( 6.3 x 10 5 ) = (193.7 x 10 5) / (1.937 x 10 7)
MULTIPLICATION
The most common operations are multiplication/ division.
Rules:
1. To multiply exponentials, ADD the exponents.
2. To divide exponentials , SUBTRACT the exponents.

Ex. Multiplication
a. (1.2 x 10 5 ) (2.0 x 10 9 )
First multiple the coefficient (1.2)(2.0)
Then add the exponents 10 5 x 10 9 = 10 14
The complete answer is 2.4 x 10 14
Division :
b. 8.0 x 10 11
1.6 x 10 4
First, divide the coefficient 8.0/1.6 = 5.0
Then, subtract the exponents 10 11- 10 4 = 10 7
The complete answer is 5.0 x 10 7

Formula : a. (x a ) (x b ) = x a+b
b. x a / x b = x a-b

SIGNIFICANT FIGURE

Rules:
1. All digits that are not zero are significant, regardless of the location of a decimal point.
Ex. 1.59 = 3 significant figures
15.9 = 3 significant figures
3.14273 = 6 significant figures
2. Zeros between non-zero digits are significant.
Ex. 20.6 = 3 significant figures
0.60 = 2 significant figures
50.0002 = 6 significant figures
3. Zeros to the left of a decimal point or to the left of a number are not significant.
Ex. 0.0517 = 3 significant figures
0. 3091 = 4 significant figures
4. Zeros to the right of a decimal point are significant if they are at the end of a number.
Ex. 59.0 = 3 significant figures
16.0000 = 6 significant figures
5. When a number ends in a zero or zeros that are not to the right of a decimal point, the end zero or zeros may or may not be .
Ex. 740 may or may not be contain significant figures, unless it should be written in exponentials notation 7.40 x 10 2 = 3 s.f.

ROUNDING OFF

Rules :
1. When the number dropped is less than 5, the proceeding number remains unchanged.
Ex. 1.874 - is rounded off to 1.87
0.056452 - is rounded off to 0.05645
2. When the number dropped is more than 5, 1 is added to the proceeding number.
Ex. 4.7438 - 4.744
0.0526 - 0.053
3. When the number dropped is exactly 5, if the proceeding number is EVEN. It remains unchanged; if the proceeding number is ODD, 1 is added to it.
Ex. 7.245 - is rounded off to 7.24
17.7735 - is rounded off to 17.774

ADDITION AND SUBTRACTION

1. In addition and in subtraction, the answer should be rounded off as to contain the same number of decimal point as in the number with the least number of decimal point.
2. The least number of decimal places in the same problem is two, so the answer be rounded off to two decimal places.
Ex. a. 12.376
+ 9.51 ( least of decimal places)
21. 886 ( to rounded off)

21.89 (correct answer)

b. 127.5093
- 61.425 ( least of decimal places)
66.0843

66.084 (correct answer)

MULTIPLICATION AND DIVISION

1. In multiplication and division, the answer should be rounded off so as to contain only as many significant figures as the number with the least number of significant figure.

Ex. 5.29 (least significant figure)
X 11.276
59.64475
The number of significant figure in this problem is three, so the answer should be rounded off to three significant figures.

59.6 ( correct answer)

Ex. 127.62/ 25.67513 = 4.9705687 4.9706 ( correct answer)


UNIT OF TEMPERATURE AND ENERGY

On freezing and boiling point of water the difference between these two points was divided in 100 points and so the scale was called the CENTIGRADE SCALE. ( Latin name called a hundred)

1948- the centigrade scale was designated as the Celsius scale (0C) in honor of the Swedish
Astronomer ANDRES CELSIUS- who develop the scale in 1742. one advantage: is that temperature below the freezing point water 00C are negative.

TEMPERATURE
Is the property that determines the direction of the spontaneous flow of heat.

HEAT ENERGY
Celsius scale, which is of a body, is the type of energy that flows a hotter body to a cooler one.
CELSIUS OC
Celsius scale which is also sometimes referred to as the “Centigarde scale” name after the Swedish astronomer ANDRES CELSIUS ( 1701-1744).

- 100 divisions
- Formula: 5/9 (0F-32) or 0F- 32
1.8
FARENHEIT 0 F
Name after German Physicist GABRIEL DANIEL FARENHEIT
- Formula : 9/5 0C + 32 or 1.8 0C + 32

KELVIN ( K)
- Kelvin scale (absolute scale) . British Physicist and Mathematician WILLIAM THOMPSON (1824-1907) who was later titled “ LORD KELVIN”.
- Formula : 0C + 273

DENSITY
D = M/V
M = DXV
V = M/D