3/26/2015
Calculating Percentage
Composition
Learning Goal:
I will be able to use the molar mass to determine the
percentage of each element in a compound.
Percentage Composition
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The percent composition of a component
in a compound is the percent of the total
mass of the compound that is due to that
component.
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3/26/2015
Steps to Use
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Find the molar mass of the compound
byy addingg upp the masses of each atom in
the compound using the periodic table
Calculate the mass due to the
component in the compound you are
for which you are solving by adding up
the mass of these atoms.
Divide the mass due to the component
by the total molar mass of the
compound and multiply by 100.
Example 1
y
Calculate the percent by mass of each
element in CaCl2
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Example 2
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Sodium bicarbonate is used in many
commercial preparations.
preparations Its formula is
NaHCO3. Find the mass percentages
(mass %) of Na, H, C, and O in sodium
hydrogen carbonate.
Today’s Task Percentage
Composition
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(NH4)2SO3 N=24.12%, H=6.96%, S=27.61%, O=41.33%
Al(C2H3O2)3 Al=13.22%,
Al 13 22% C=35.30%,
C 35 30% H=4.45%,
H 4 45% O=47.03%
O 47 03%
NaBr Na=22.34%, Br=77.66%
Cu(OH)2 Cu=65.13%, O=32.80%, H=2.07%
MgCO3 Mg=28.83%, C=14.24%, O=56.92%
Fe3(PO4)2 Fe=46.87%, P=17.33%, O=35.80%
Be3N2 Be=52.95%, N=47.05%
KCN K=60.04%,
K 60 04% C=18.44%,
C 18 44% N=21.52%
N 21 52%
Mn(NO3)3 Mn=22.80%, N=17.44%, O=59.76%
Li3P Li=40.20%, P=59.80%
Ni2(SO4)3 Ni=28.94%, S= 23.72%, O=47.34%
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