[MOD1] GENCHEM SUMMARY

Chemistry

Study of matter, its properties & changes it undergoes

Matter

Anything that occupies space & has mass

Solid

Rigid with definite form /shape, fixed volume resist flow; virtually incompressible

Liquid

No definite form /shape ; assumes the shape of its container; fixed volume; intermediate properties

Gas

no definite shape and volume; can diffuse & fill the container where it is placed; very compressible; particles move independently of one another

States of matter

sold, liquid, gas

Properties of matter

physical, chemical, intrinsic, extrinsic

Physical

inherent in the substance & can be determined without altering the ◦ f- more than one atom of an element compound

Chemical

ability of a substance to interact with other substance to form a different • substance

Intrinsic

independent of the amount of matter; eg. Density ,pH , color. boiling point,melting point ,freezing point

Extrinsic

Dependent of the amount of matter; eg. volume, weight, pressure

Substance

form of matter that has a definite composition & distinct properties

Pure substance

Has fixed composition & can not be separated into simpler substance by physical method

Elements

Substance that cannot be broken down

Compound

Substance that consist of 2 or more atoms of elements at fixed ratio

Mixture

Combination of 2 or more substance in which each substance retain its own property

Homogenous

Have same composition throughout; Components are indistinguishable

Heterogenous

Do not have same composition throughout; Components are distinguishable

Physical

Changes in physical properties or changes in the state without accompanying change in composition

Melting

S → L

Evaporation

L → G

Freezing

L → S

Condensation

G → L

Sublimation

S → G

Deposition

G → S

Chemical

New substance are formed that have different properties & composition from the original material

Evidence of chemical change

evolution of gas; emission of light; formation of precipitate; generation of electricity; production of mechanical energy; absorption/liberation of heat

Oxidation

Chemical union of oxygen with another substance; Loss of electron

Reduction

oxygen is removed from a compound or H+ is added; gain of electron

Neutralization

Acid react with base to form salt & H2O

Hydrolysis

Reaction of water & salt to form acid & base

Saponification

Reaction between alkaline pots/oil forming soap glycerol (5- KOH ; It - NaOH)

Fermentation

Action of bacteria /microorganism on organic substance resulting to the production of alcohol

Synthesis/Combination/Direct Union

A + B → AB

Decomposition/Analysis

AB → A + B

Single Displacement

AB + X → AX + B

Double Displacement/Exchange/Metathesis

AB + CD → AD + CB

Nuclear

Change in structure,properties,composition of the nucleus of atom resulting in the elements transmutation to another

Nuclear Fission

Splitting of a heavy atom

Nuclear Fusion

Union of 2 light atoms to form a bigger molecule

Elements

Fundamental substance that cannot be broken down into simpler substance

Dmitri Mendeleeve

designed periodic table & arranged elements according to their atomic no. & in groups by their chemical properties

Classification of elements

by representative, transition element, or by special groups with similar properties

Metal

High luster ; good conductor of heat & electricity

Non-metal

not lustrous; poor conductor of heat & electricity

Metalloid

Has properties of both metal & nonmetal

Compound

Substance that contains 2 or more elements chemically combined in a definite proportion by mass

Molecular

Formed from individual molecules composed of atoms

Ionic

Formed from ions that are either positively or negatively charged

Cationic

positively charged ion

Anionic

negatively charged ion

Characteristic of chemical formula

contains symbols of all elements in the compoint; symbol represents one atom of the element; if more than one atom of an element is present,the number of atoms is indicated by a subscript; parentheses are used to show multiple groups of atom occurring as a unit in the comp.; a formula does not show the arrangement of atoms in a compound

Molecular Formula

Formula based on the actual molecule; gives thee actual number of atoms of each element

Empirical Formula

Simplest formula; Based on formula units; gives the smallest whole number ratio

Structural Formula

Arrangement of atoms in a molecule of a compound

Electron Dot Formula

Shows the distribution of electrons in the outermost shell of the atom

Four Elements

Earth, Wind, Water & Fire

Democritus

"atoms" (indivisible particles) make up matter

Aristotle

opposed the atomic theory

Dalton's atomic theory

Elements are composed of indivisible, indestructible atoms; atoms of the same elements are alike; atoms of different elements differ in size, mass & other properties; compounds are formed from two or more atoms of different elements; atoms combine in single numerical ratios to form compound

Antoine Lavoisier

created Law of Conservation of Mass

Law of Conservation of Mass

Mass of material before a reaction is equal to the mass after; Mass is neither created nor destroyed

Joseph Proust

created Law of Definite Composition

Law of Definite Composition

Chemical compound ,regardless of source or method of preparation have the same composition

Law Of Multiple Proportion

If two elements from more than one compound, masses of an element in combination with the fixed mass of another are in ratio of small whole number

J.J.Thomson

used cathode ray tube to determine charge to mass ratio of electrons' "Canal ray" associated with proton H+, Plum pudding model

Plum Pudding Model

Atoms are (+) charged embedded with (-) charge

RA Millikan

oil drop experiment

Oil drop experiment

Measures accurate mass op electrons

Wilhelm Roentgen

Very penetrating rays from CRT not deflected by magnet - " X-ray "

Henri Becquerel

Chemical decomposing spontaneously giving off penetrating rays

Marie Curie

studied uranium & thorium; radioactivity

Ernest Rutherford

alpha Scattering Experiment; nuclear atomic model

Nuclear atomic model

Empty space; concentrated mass with protons in one area ;Opposite of Thompson Model

Niels Bohr

Planetary Model

James Chadwick

Discovered Neutrons

Electrons

negatively charged; 1/1837 mass or proton; discovered by J.J. Thompson

Protons

positive charge; 1.637 x 10-24, discovered by Ernest Rutherford

Neutrons

no change; 1.675 x 10-24, discovered by James Chadwick

Atomic Number

# of proton

Mass number

# of protons + number of neutrons

Atomic mass

average mass of all isotopes of one element that approximates mass number

Nucleon

proton & neutron

Isotope

atoms of the same element but different number of neutrons

Isotone

atoms with the same number of neutrons

Isobar

Atoms of different elements with the same atomic mass but different atomic no.

Molecule

Aggregate of two or more atoms in definite arrangement held together by Chem . bond

Principal quantum number (n)

main energy level;determines the size of a particle/electron cloud, distance of electrons from the nucleus, represented by a positive integer

Angular Momentum/Azimuthal (l)

subshell/sublevel, determines the shape; represented by 0-(n-1)

Magnetic quantum number

orientation of orbital in space; represented by a (+) or (-) integer value

Spin orientation quantum number (ms)

Determines the direction of spin or rotation; +½ or -½

Heisenberg's Uncertain

impossible to determine simultaneously the momentum & position of an electron

Pauli's Exclusion Principle

No two electron can have the same quantum number; each atomic orbital accommodates 2e-

Aufbau's principle

lower energy level are filled up first

Hund's rule

Orbitals are piled up singly before pairing up

Antoine Laurent Lavoisier

Constructed the 1st periodic table; metal vs non-metal (~33 elements)

Johann Dobereiner

"Triad", Li, Na, K; Ba,Ca,Sr; S, De, Te

John Newlands

"Octaves"

Dmitri Mendeleev

Father of the Periodic table

Meyer & Mendeleev

Physical & chemical properties are periodic function of their atomic weight