Chap3 - Divide weight in grams by atomic weight Finding...

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Sheet1 Page 1 Chapter 3: Stoichiometry -Numbers and quantities associated with chemical formulas and equations Atomic Mass: Standard system in 1961: (superscript 12)C is assigned a mass of exactly 12 atomic mass units (amu) -THe masses of all other atoms rleated to the standard (superscript 12)C Mass Spectrometer: Instrument used to measure the masses of atoms Atomic mass = Atomic weight Definition of Average Atomic Mass: A) The weighted average of the atomic masses of all the isotopes of the element B) E(Sigma)[(isotope mass) x (fractional isotope abundance)] for all isotopes of the element. Calculation of average atomic mass: A) Naturally occuring Bromine consists of 50.69% amu and 49.31% (superscript 81)Br of atomic mass 80.92 amu. Calculate t h Mole: -THe amount of substance that contains as many particles as the number of atoms in exactly 12g of (superscript 12)C. Avogadro's number: 6.022 x 10^23 Finding mol of an element:
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Unformatted text preview: Divide weight in grams by atomic weight Finding atoms: How many atoms of Potassium are present in 6.3mol of K 6.3 x atomic weight of K Molar mass: The sum of the atomic masses of each element in one mole of a compound expressed in grams. Units: g/mol Calculating Molar Mass: NH4NO3 (ammonium nitrate) (take atomic weight from each element and add them to obtain compound's weight) N: 14.008 H(4): 1.0080 N: 14.008 O(3): 16.00-Add these Chemical Equations: Shorthand representation of a chemical reaction. Atoms undergo reorganization. Bonds are broken and reformed Empirical Formula: Simplest formula of a compound which will show the relative whole number of each element in 1mol of a compound Molecular Formula: A formula that shows the actual number of each element present in 1mol of the compound ElementCarbonHydrogenOxygen Sheet1 Page 2 Percent48.648.1643.20 Atomic Weight12.011.00816.00...
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This note was uploaded on 05/06/2008 for the course CHEM 151 taught by Professor Campbell during the Spring '08 term at Lansing.

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Chap3 - Divide weight in grams by atomic weight Finding...

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