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chloe ko.
christina chow.
mr. doktor's chemistry class
block g

home. mrdoktor.

-the percentage by mass of an element in a compound is always the same
-to find the percent by mass determine the mass of each element present in one mole

Example:
Find the percentage composition of a compound that contains 2.88g of gold in a 6.20-g sample of the compound.

2.88g/ 6.20g = 0.4645
                     = 46.4%  [multiply by 100 to get percentage]

Determine the mass of Hydrogen present in a 5.1g sample of Water .
2g/ 18g = 0.11%
            = (0.11)5.1g = 56.1g
                                = 56g

Find the percentage composition of a compound that contains 3.36g of Berylium in a 9.99g sample of the compound.
3.36g/ 9.99g = 0.3363
                     = 33.6%