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Описание: Importance of Chemistry
Chemistry is the study of matter and its changes.
It helps us understand the composition, structure, and properties of substances.
Applications include medicine, agriculture, industry, environment, and daily life products.
2. Branches of Chemistry
Organic Chemistry – Study of carbon compounds.
Inorganic Chemistry – Study of all elements except most carbon compounds.
Physical Chemistry – Study of energy changes and laws of chemistry.
Analytical Chemistry – Identification and measurement of chemical substances.
Biochemistry – Study of chemical processes in living organisms.
3. Scientific Method
Observation
Hypothesis
Experiment
Theory and Law
A theory explains why something happens.
A law describes what happens based on repeated experiments.
4. SI Units (International System of Units)
Physical Quantity
Unit
Symbol
Length
meter
m
Mass
kilogram
kg
Time
second
s
Temperature
kelvin
K
Amount of substance
mole
mol
5. Significant Figures
All non-zero digits are significant.
Zeros between non-zero digits are significant.
Leading zeros are not significant.
Trailing zeros are significant if a decimal point is present.
Used to show accuracy in measurements.
6. Scientific Notation
Used to express very large or very small numbers.
Written in the form:
Example:
6000 = 6 × 10³
7. Laws of Chemical Combination
Law of Conservation of Mass – Mass is neither created nor destroyed.
Law of Definite Proportions – A compound always contains elements in fixed ratio.
Law of Multiple Proportions – Elements combine in small whole number ratios.
8. Atomic Structure Basics
Atom consists of proton, neutron, and electron.
Atomic number = number of protons.
Mass number = protons + neutrons.
Isotopes: Same element, different mass numbers.
9. Mole Concept
1 mole = � particles (Avogadro’s number).
Molar mass = mass of one mole of substance.
Used to calculate number of atoms, molecules, or ions.
10. Empirical and Molecular Formula
Empirical formula – Simplest whole number ratio of atoms #chemistrychamps #fypシ゚viral #trending #chemistrychamps #chemistrycrashcourse #exam chemistry lectures hub