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15 Cards in this Set
- Front
- Back
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Democritus
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Greek Philosopher - all matter is actualy composed of tiny indivisible particles called ATAMOS (450 BC)
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Alchemists
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Tried to turn ordinary metals into gold (400 BC)
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Antoine lavoisier
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Law of conservation of matter - matter is neither created nor destroyed in a chemical reaction (1783)
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Joseph Louis Proust
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Law of constant composition - Compoinds always contain the same elements in the same proportion by mass - eg. Water is always 88.9% oxygen and 11.1% hydrogen.
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John Dalton
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Atomic theory of matter
-Each element is composed of extremly small particles called atoms -All atoms of a given element are identical, but they differ from those of any other element (false) -Atoms are neither created nor destroyed in any chemical reaction -A given compound always has the same relative numbers of kinds of atoms. |
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Michael Faraday
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Atomic structure is related to electricity (1839)
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William Crooks
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-Developed the cathode ray tube (crookes tube)
-Performed experiments involving the flow of electric current through glass... Gasses sealed in glass tubes with metal discs at each end...Electrodes are conected to a high voltage source of electricity...a stream of charged particles flows from the cathode(-) to the anode(+) |
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J.J. Tompson
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magnetic and electric fields deflected the path of the cathode ray tube.
-DISCOVERED negativly charged particles named ELECTRONS -Plum pudding model - negativly charged electrons floating in a positive material. |
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Henri Bacquerel
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Natural Radiation from uranium ores (Radioactivity)
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Ernest Rutherford
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3 types of radiation
-Alpha (Positive) -Beta (Negative) -Gamma (Neutral)most dangerous. ---Gold Foil experiment--- aimed alpha(+) particles thin gold paper..Expected alpha would pass straight through..small amound deflected (1/8000) -concluded all atoms have a + charge in a very small core -((NUCLEUS))- atom is mostly empty space |
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Error Formula
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-ABSOLUTE error
|measured value-accepted value| -PERCENT error (Absolute error/accepted value) X100 |
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SigFigs In addition/subtraction
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answer has same number of DECIMAL PLACES as the measurement with the least number of decimal places - eg. 97.542-22.44=75.102 = 75.10
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SigFigs In Multiplication/Division
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Answer has same number of SIGFIGS as the measurement with teh least number of sigfigs -eg. 2.5674cm x3.5cm x3.54cm =32cm^3
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Ions
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When an atom loses or gains one or more electrons it acquires a net electrical charge called and anion - Charge = #protons -#electrons
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Isotopes
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Atoms of the same element that contain different numbers of neutrons
Hydrogen 1p+ 0 n0 Deutrerium 1p+ 1 n0 Tritium 1p+ 2 n0 |
