A sample of rest of the following composition 51.85 g of iron 22.22 g of oxygen 16.67 g of water

To calculate the percent composition, we need to know the masses of C, H, and O in a known mass of C9H8O4. It is convenient to consider 1 mol of C9H8O4 and use its molar mass (180.159 g/mole, determined from the chemical formula) to calculate the percentages of each of its elements:

%

C

9

mol C

×

molar mass C

molar mass

C

9

H

18

O

4

×

100

=

9

×

12.01

g/mol

180.159

g/mol

×

100

=

108.09

g/mol

180.159

g/mol

×

100

%

C

60.00

%

C

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