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
Percent Composition Calculations

1 (a)
Determine the percent composition of ammonia gas, NH3.
(b)
Determine the percent composition of ammonium nitrate, NH4NO3.
(c)
Determine the percent composition of ammonium sulfate, (NH4)2SO4.
(d)
Determine the percent composition of urea, N2H4CO.

2. Each of the compounds listed in question 1 contains nitrogen. They are used as fertilizers. For each of the compounds, which one has the highest percentage of nitrogen?
Chlorine (Cl) is the active ingredient used to purify water in swimming pools. Three brands are available and each cost $0.50 per liter of water solutions of NaOCl.
  • Brand A contains 10 % OCl- by mass,
  • Brand B contains 7 % chlorine (Cl) by mass,
  • Brand C contains 14 % NaOCl by mass.

Which of the three brands is the best buy?

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