Chemical Formulas and Chemical Compounds

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Chapter 7 Chemical Formulas and Chemical
Compounds NearingZero.net
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Section 1Chemical Names and Formulas

• Chemical Formulas
• C6H12O6 Al2(SO4)3

Subscript indicates that there are 6 carbon atoms
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Monatomic Ions

• Positive Ions
• Write the name of the element
• Write the word ion
• Na Sodium ion
• Transition elements use Roman Numerals
• Fe 2 Iron (II) ion

• Negative Ions
• Write the name of the element
• Change the ending to ide
• Write the word ion
• Cl- Chloride ion

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Binary Ionic Compounds

• 2 elements Binary
• Metal nonmetal ionic
• Write the name of the 1st element
• Write the name of the 2nd element
• Change the ending to ide
• NaCl Sodium Chloride
• MgCl2 Magnesium Chloride

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Stock System

• Uses roman numerals
• Write the name of the 1st element
• Write the oxidation number of the 1st element
• Write the name of the 2nd element
• Change the ending to ide
• CrF3 Chromium (III) Flouride
• NiF

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Binary Molecular Compounds

• Molecular covalent PG 212 Prefixes
• Write the name of the 1st element
• Write the name of the 2nd element
• Change the ending to ide
• Put in prefixes
• Only use prefixes on the 1st element if it is
  more than 1
• NO2 Nitrogen Dioxide
• N2O3

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Binary Acids

• Acids always begin with H
• Acids that consist of 2 elements
• Write hydro
• Write the 2nd element
• Change the ending to ic
• Write the word ACID
• HF Hydrofluoric Acid
• HBr

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Oxyacids

• Are acids that contain hydrogen, oxygen, and a
  third element.
• Never use Hydro
• Write the name of the polyatomic (pg 210)
• Change the ending to ic or ous (ate -ic ite
• ous)
• Write the word ACID
• H2SO4 sulfuric acid
• H3PO4

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Polyatomic Compounds

• Write the name of the 1st element
• Write the name of the polyatomic (pg 210)
• NaNO3 Sodium Nitrate
• AgNO2

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Section 2 Oxidation Numbers

• Oxidation numbers- are assigned to the atoms in
  molecules, including molecular ions, to show the
  general distributions of electrons among the
  bonded atoms.

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/- 4
2
3
-3
-2
-1
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Oxidation numbers

• Rules pg 216
• UF6
• UF6 criss cross the numbers up
• Check the 2nd element using the periodic table
• U 6 F -1
• Polyatomic compounds do a math line
• 3 -8 0 H 1 P 5
  O-2
• 1 -2
• H3PO4
• If there is an ION (charge) do a math line

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Practice oxidation numbers

• GeCl2
• CS2
• ClO3-
• H2SO4
• PCl3
• HNO3
• GeO
• SO4-2
• NO2-

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Section 3 Using Chemical Formulas

• Formula mass (molar mass or weight) of any
  compound or polyatomic ion is the sum of the
  average atomic masses of all the atoms
  represented in the formula.
• H20 H x 2 2.014g
• O x 1 15.999g
• 18.013 g of H2O

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Old stuff

• Mole to grams
• Grams to moles
• Moles to particles
• Particles to moles
• Grams to particles
• Particles to grams

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Percent Composition

• comp Mass of element in the sample
• mass of sample (formula mass)
• Calculate the comp of H2O

X 100
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Section 4 Determining Chemical Formulas

• Empirical Formula- (simplest formula) consists of
  the symbols for the elements combined in a
  compound, with subscripts showing the smallest
  whole-number mole ratio of the different atoms in
  the compound.
• C2H6 simplest formula would be CH3

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Empirical Formulas

• Drop the signs and add grams
• Covert to moles of each element
• Take the smallest number of moles and divide it
  into all the other values
• Write the formula
• Determine the empirical formula for a sample
  that contains 78.1 B 21.9 H

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Molecular Formulas

• Do the same 4 steps for determining empirical
  formulas
• Add up the formula mass of the empirical formula
• Use the molecular formula mass in the question
• Use the formula X Molecular formula mass
• empirical
  formula mass
• Use the x and multiply your empirical
  formula using it

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• Cartoon. Aug. 11, 2006. http//www.nearingzero.n
  et/sbunch5.html