Percent Composition Notes

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Percent Composition Notes
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Ipod or MP3 Player?

• Would you rather have an IPOD or an MP3 Player?
• IPOD
• MP 3
• How do I calculate the percentage of votes?

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Calculate a Percent

• Divide the part by the whole
• Multiply by 100

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Percent Compostion noun

• Relative measure of the mass of each different
  element present in the compound.

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To calculate

• Calculate the total mass of each element present
  in the formula
• Add the masses to get Molar Mass of compound
• by weight (mass) of element
• (total mass of element molar mass) x 100

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Composition Example
1. What percentage of CaCl2
does Calcium make up? Ca 1 x 40 40 (40/110)
x 100 36 Cl 2 x 35 70 (70/110) x 100
64 110g 100
Molar Mass Explanation Practice
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You Try it!

• What is the percent composition of each element
  in ZnBr2?
• What is the percent composition of each element
  in NaHCO3?

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Solution

• ZnBr2?
• Zn 1 x 65 65 (65/225) x 100 29
• Cl 2 x 80 160 (160/225) x 100 71
• 225g 100
• 2. NaHCO3?
• Zn 1 x 23 23 (23/84) x 100 27
• H 1 x 1 1 (1/84) x 100 1.2
• C 1 x 12 12 (12/84) x 100 14

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O 3 x 16 48 (48/84) x 100 57

• 84g 100

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Homework

• Calculate Composition
• H2S
• HCN
• (NH4)2C2O4
• Mg(OH)2
• Na3PO4
• Ca(C2H3 O2)2