Define Percentage Composition in Compound.

1.	Define Percentage Composition in Compound.
Answer» Solution :So far, we were dealing with the number of entities PRESENT in a given sample, But many a time, the information regarding the percentage of a particular element present in a compound is required. One can check the purity of a given sample by analysing this data. Let us understand it by taking the example of water `(H_(2)O)`. Since water CONTAINS hydrogen and oxygen, the percentage composition of both these elements can be calculated as follows : Mass % of an element `=("mass of that element in the compound" xx 100)/("molar mass of the compound")` Molar mass of water `= 18.02g` Mass% of hydrogen `=(2xx1.008)/(18.02)XX100=11.18` Mass % of oxygen `=(16.00)/(18.02)xx100=88.79` The percentage of carbon, hydrogen and oxygen in ethanol : MOLECULAR FORMULA of ethanol is `=C_(2)H_(5)OH` Molar mass of ethanol `=(2xx12.01 + 6 xx 1.008+16.00)g` `=46.068g` Mass percent of carbon `=(24.02)/(46.068)xx100` `=52.14%` Mass percent of hydrogen `=(6.0489)/(46.0689)xx100` `=13.13%` Mass percent of oxygen `=(16.00 g)/(46.068 g)xx100` `=34.73%`

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