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Percent composition. C-notes on page 64. Example : Find the % composition of all of the elements within a glucose molecule using the molecules molar mass. You will have to know how to do this to complete future objectives. Glucose: molecular formula = C 6 H 12 O 6
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Percent composition C-notes on page 64
Example: Find the % composition of all of the elements within a glucose molecule using the molecules molar mass. You will have to know how to do this to complete future objectives. • Glucose: molecular formula = C6H12O6 • (will be given information) • Find the molar mass of the compound • Find the % of each element with in the compound: element mass x 100 = %composition molar mass
Glucose: molecular formula = C6H12O6 molar mass = (12.01 g/mol x 6) + (1.01 g/mol x 12) + (16.00 g/mol x 6) = 72.06 g/mol + 12.12 g/mol + 96.00 g/mol = 180.18 g/mol
% composition of carbon • 72.06 g/mol = .3999 x 100 = 39.99% carbon 180.18 g/mol
% composition of hydrogen • = 12.12 g/mol = .0673 x 100 = 6.73% hydrogen 180.18 g/mol
% composition of oxygen = 96.00 g/mol= 0.5328 x 100 = 53.28% oxygen 180.18 g/mol
Check your answer • The end result is that all parts of the compound should equal 100% (or very, very close due to rounding issues) • 53.28% + 6.73% + 39.99% = 100%
Practice problems for pg 64will be part of notes • Write the chemical formula • Find the molar mass • Find % composition of each element in compound • Sodium chloride • Aluminum hydroxide • Ammonium phosphide • Summarize notes and complete practice for stamp
Bubble gum lab • This will be turned in for a grade. • You will need 5 pieces of unchewed gum. • We will be going to the lab. While in the lab you need to do the pre lab and steps #1 and #2. • DO NOT CHEW THE GUM YET!!!!!!!!!