Profile
Settings
Refer your friends
Sign out
Percentage Composition
The proportion of an amount of each component of individual components to the total amount of individual components in a compound is known as percentage composition. This amount is then multiplied by 100.
About the Topic
The percentage composition formula is the formula used to compute the percentage composition of any given compound. Here, we measure while computing the percentage composition of any compound we measure the quantity in terms of grams unit.
The percentage composition is very useful as it helps us to determine what quantity of an element is present in a given compound.
The percentage composition formula of any compound is:
Mass of any elements × 100
The molecular mass of the compound
Solved Examples
Q1. Compute the percent composition of both carbon and oxygen in carbon dioxide.
Ans: The chemical formula for carbon is CO2.
- The first is to compute the molar mass of carbon dioxide
The molar mass of carbon = 12.011 × 1 = 12.011 g/mole and the molar mass of oxygen = 16 × 2 = 32 g/mole
- Secondly, we have to calculate the molecular mass of the compound( here carbon dioxide). The molecular mass of CO2 is 44.01 g/mol
- Now substituting the values of the mass of the elements and the total molar mass of the compound in the formula, we can find the percentage composition of carbon and oxygen
- The percentage composition of carbon is:
12.011/44.01 ×100
27.29%
The percentage composition of oxygen is:
16.00/44.01 ×100
72.71%
Q2. Compute the percentage composition of carbon in glucose.
Ans: The chemical formula of glucose is C6H12O6.
Glucose has 6 molecules of carbon, and the molecular mass of glucose is 180.156 grams.
One mole of a carbon atom weighs 12.011 grams. So, 2 carbon moles will weigh 24.022 grams.
Hence, one mole of glucose has 24.022 grams of carbon mole.
Therefore, the percentage composition of carbon in glucose would be
= 24.022/180.156 × 100 = 13.33%
