Formulas for molecular compounds

Formulas for molecular compounds - hydrogen is different...

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Formulas for molecular compounds A molecular formula shows the type and number of atoms in a molecule type of atom indicated by element symbol number of atoms per molecule indicated by subscripts (if greater than one) o H 2 O contains 2 hydrogen atoms and one oxygen atom per molecule. o Carbon tetrafluoride, CF 4 , contains four fluorine atoms and one carbon atom per molecule. atoms in formulas are sometimes grouped to show how they're connected in the molecule o Methanol is usually written as CH 3 OH to show that 3 hydrogens are bound to the carbon and another hydrogen is bound to the oxygen. o Acetic acid can be written as CH 3 COOH or as HC 2 H 3 O 2 or C 2 H 4 O 2 . The first formula shows how the molecule is put together; the second formula emphasizes that one
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Unformatted text preview: hydrogen is different from the others; the third formula is the least informative because it shows only the numbers and types of atoms in the molecule. • groups that appear more than once in the molecule are enclosed in parentheses o CH 3 (CH 2 ) 3 CH 3 could be written as C 5 H 12 , but all information about the structure of the molecule would be lost. o (CH 3 CH 2 ) 4 P 2 O 7 molecules contain 8 carbons, 20 hydrogens, two phosphoruses, and seven oxygens. • molecular weight = sum of weights of atoms in the molecule o The molecular weight of CH 3 OH is approximately 12 + 4*1 + 16 = 32 since the carbon, hydrogen, and oxygen have atomic weights of 12, 1, and 16 u, respectively...
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This note was uploaded on 11/22/2011 for the course CHEMISTRY CHM1025 taught by Professor Laurachoudry during the Fall '10 term at Broward College.

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