Unit #1Unit #2Unit #3Unit #4Unit #5Unit #6Unit #7Unit #8Unit #9Unit #10
spacerUNIT # 7  
spacerspacerIntroduction
spacerspacerObjectives
spacerspacerReading

spacer7.1 Calculation of
spacerFormula
spacerMass

spacer7.2 Mole
spacerConcept

spacer7.3 Atomic Mass
spacerRevisited

spacer7.4 Calculation of
spacerMolar Mass
spacer
7.5 Calculations
spacerinvolving
spacerAvogadro #

spacerMass to mole conversion and vice-versa
spacermole to number of particles conversion and vice-versa
spacerMass in grams to number of particles conversion
spacer
7.6 Molar Volume
spacerof a Gas
spacerMolar volume calculations
spacer
7.7 Percent
spacerComposition
spacer
7.8 Empirical
spacerFormula

spacer7.9 Empirical
spacerMass to
spacerMolecular
spacerFormula



spacerProblems
spacer1 | 2
| 3 | 4 | 5

Unit # 7 - Calculations Based on Formulas
Empirical and Molecular Formulae

Write the empirical formula for each of the following.
1.(a)
C8H18, octane
(b)
C12H22O11, sugar
(c)
H2S, hydrogen sulfide
(d)
C2H6O2, ethylene glycol (antifreeze)

2. From the following empirical formulas and the formula masses for each compound, determine their molecular formulas.
(a)
CH3; formula mass= 30.0 amu
(b)
CH2; formula mass= 84.0 amu
(c)
C3H4O3 (Vitamin C); formula mass= 176 amu

3. Determine the empirical formula for a compound that contains 18.6 g of phosphorus and 14.0 g of nitrogen.

4. Determine the empirical formula for a compound that contains 35.6 % of phosphorus and 64.4 % of sulfur.

5. A compound with a molecular mass of 98.0 g/mole was determined to be 24.49 % carbon, 4.08 % hydrogen, and 72.43 % chlorine.
(a) Determine the empirical formula of the compound.
(b) Determine the molecular formula of the compound.

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