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Percent Composition Calculator

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This online Percentage composition calculator determines the mass of each element present in the compound, expressed in percentage. To find the percent composition, we have to find the mass of each element then the total molar mass of the compound.

Percentage Composition Formula :

Percentage Composition = $\frac{Mass \ of \ each \ element}{Molecular \ mass \ of \ compound }$
 

Steps

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Step 1 : Determine the molecular mass of the compound by using the atomic mass given in the periodic table.

Step 2 : Then, determine the mass of each element. Then by using the percentage composition formula given above, substitute the values and get the percentage of particular element.

Problems

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Below are the problems based on percent composition .

Solved Examples

Question 1: Determine Percentage composition of carbon in $CO_{2}$ .
Solution:
Step 1 :  Given elements are C and O.
Atomic mass of Carbon C = 12.01 amu and Oxygen O = 16.00 amu.

Molecular mass of compound =  12.01 + 2 $\times$ 16.00
                            = 44.01 amu.

Step 2 :  Mass of Carbon in $CO_{2}$ = 12.01 amu.

Percentage composition of Carbon in $CO_{2}$ is,

=  $\frac{Mass \ of \ each \ element}{Molecular \ mass \ of \ compound }$ $\times$ 100 %

=  $\frac{12.01 \ amu}{44.01 \ amu}$ $\times$ 100%

= 40 %.


Question 2: Calculate the Percentage composition of sodium and chlorine in $NaCl$ ?
Solution:
Step 1 : Given elements are Na and Cl.
Atomic mass of Sodium Na = 22.99 amu and Chlorine Cl = 35.45 amu.

Molecular mass of compound =  22.99 amu + 35.45 amu
                            = 58.44 amu.

Step 2 : Mass of Sodium in $NaCl$ = 22.99 amu.

Percentage composition of sodium in NaCl is,

= $\frac{Mass \ of \ each \ element}{Molecular \ mass \ of \ compound }$ $\times$ 100 %

= $\frac{22.99 \ amu}{58.44 \ amu}$ $\times$ 100%

= 39.34 %.

Mass of Chlorine in $NaCl$ = 35.45 amu.

Percentage composition of chlorine in NaCl is,

= $\frac{Mass \ of \ each \ element}{Molecular \ mass \ of \ compound }$ $\times$ 100 %

= $\frac{35.45 \ amu}{58.44 \ amu}$ $\times$ 100%

= 60.66 %.