C3_stoich_active_fillin.pdf - Stoichiometry Learning Objectives You should be able to \u2022 identify the number of atoms present in a chemical formula \u2022

# C3_stoich_active_fillin.pdf - Stoichiometry Learning...

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Stoichiometry S1 - The Mole Number of atoms equal to 1 mole of anything = 1 mole C = 6.022 x 10 23 C atoms = Calculate the number of iron atoms in a 4.48 mole sample of iron. S2 - Molar Mass Mass in grams of one mole of the substance: Molar Mass of N = Molar Mass of H 2 O = Molar Mass of Ba(NO 3 ) 2 = Rank the following according to number of atoms (greatest to least): a) 107.9 g of silver (MM = 107.86 g/mol) b) 70.0 g of zinc (65.38 g/mol) c) 21.0 g of magnesium (24.305 g/mol) Consider separate 100.0 gram samples of each of the following: H 2 O (MM=18 g/mol) and CO 2 (MM=44 g/mol) Rank them from greatest to least number of oxygen atoms. Learning Objectives You should be able to: identify the number of atoms present in a chemical formula convert moles to number of particles/molecules/etc to moles
Stoichiometry S3 - Mass Percent Mass percent of an element: For iron in iron(III) oxide, (Fe 2 O 3 ): Consider separate 100.0 gram samples of each of the following: H 2 O, CO 2, N 2 O Rank them from highest to lowest percent oxygen bymass. S4 - Empirical and Molecular formula Example: benzene Empirical formula = Molecular formula = Learning Objectives You should be able to: define and calculate mass percent values from chemical formula differentiate between molecular and empirical formulae determine empirical and molecular formula from mass percent and combustion analysis data S5 - Empirical Formula General rules for Empirical formula from starting from mass percentvalues: Assume 100 g of total compound Calc. # of moles of each element Divide each value of moles by smallest value If all values are whole numbers, the number for each element is thesubscript If not, multiply by an integer to get whole numbers
Stoichiometry S7 - Empirical and molecular formulae The composition of adipic acid (precursor for industrial production of nylon) is 49.3% C, 6.9% H, and 43.8% O (by mass). The molar mass of the compound is about 146 g/mol. What is the empirical formula?

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• Fall '08
• Kenney