Chemistry: is the study of matter and the changes that matter undergoes. Matter is made up of almost infinitesimally small building blocks called atoms. Atoms can combine together to form molecules. Molecules of a few familiar substances are represented here. In later chapters you will learn more about how atoms combine to form molecules, and how molecules have the shapes and properties that they do
Main Branches of chemistry: (1) Inorganic chemistry (2) Physical chemistry (3) Organic chemistry (4) Biochemistry (5) Analytical chemistry (6) Agricultural chemistry
(7) Industrial chemistry, (8) Nuclear Chemistry
Scientific Methods: The scientific method consists of the following five steps :
i- To accumulate information through observation
ii – To organize this information and to seek regularities in it;
iii – To wonder why regularities are there.
iv – To frame hypothesis, theories and laws
v – To communicate the knowledge to others.
Law: It is a brief statement that can be accepted as general truth.
Hypothesis: It is a provisional conjecture (based upon· available data) to explain the known facts about a phenomenon,
Theory: Theory is the result of testing and retesting the hypothesis by experiments under different conditions.
Role of Chemistry : the rule of chemistry can be summarized as below :
a – population explosion : Chemistry has solved this growing population by new birth controlling drugs.
b – Food for millions: Chemists have developed new fertilizers such as urea etc, and effective insecticides such as DDT fur better agriculture.
c – Treatment of diseases: Chemists have saved man from dreadful diseases such as malaria, T.B ., Typhoid. They have produced wonderful drugs like penicillin, vitamins, hormones etc.
d – Environmental pollution: Chemists are dedicated in devising new methods for checking air and water pollution.
e – Energy resource: The chemists are trying to Exploit new sources· of energy like sea, air etc. meet the demand of .energy.
Father of chemistry: Robert Boyle .
Founder of modern chemistry: Lavoisier.
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