The purpose of describing the percentage composition of a given substance is to determine how much of each element it contains. This knowledge is crucial in various stages of chemical analysis. The percentage composition helps the students to identify the percentage of the elements present in a particular compound. It can be used in several chemical reactions. Some examples of the chemical compound are given below in the material.

• Determining the nature and amount of elements in a compound provides essential information about its reactivity, use, and toxicity
• The description of the percentage composition or the formula of a compound is also used in several different types of chemical reactions such as oxidation, acid-base reactions, and many more
• In this process, the elements present in a compound are calculated and determined in percentages represented by the formula, which is usually found by the atomic weights
• These elements may be metals, non-metals, metals, or semimetals
• The percent composition of the compound is used to find out all the impurities existing in it, as well as its purity
• This type of analysis of a given compound helps to determine how to purify it from all other impurities existing in it and gives us better output in terms of percentage
• The percent composition formula can be taken out as :

% Ce = Ge/Gt * 100

%Ce = Percentage composition of an element

E = amount to be calculated

Ge = Amount of the substance present in the compound

Gt = Total amount of all the elements present in the compound out there

For example, the butane C4H10, the percentage composition of a compound formula, can be calculated according to it. The formulae are :

• Mass of H according to one mole : 10 atoms of hydrogen = 10 mol H * 1.0079 g/ 1 mol H = 10.078 g H
• Mass of C according to one mole: 4 atoms of carbon = 4 mol C * 12.001g/1 mol C = 48.044 g C
• Mass Percentage of H in Butane = 10.079 g H/58.123 g Butane * 100 = 17.3% of H
• Mass Percentage of C in Butane = 48.044 g C/58.123 g Butane * 100 = 82.7% of C

So, we can say that by the percent composition formula, we can say that Butane contains 17.3% of Hydrogen and 82.7% of Carbon. The percentage composition formula can be used on the other compounds to calculate the percentage of an element present in the compound.

Mass Percent 

A percent by mass of a compound can be determined directly by weighing an accurately weighed amount of the unknown compound in a known mass of an accurately weighed pure standard, and calculating the percentage of the unknown compound by dividing this value (which is the unknown sample’s molecular weight) by the total molecular weight of the combined substances. 

•  The Mass percent of an element in a compound, is the mass of an element in a given formula unit against the total mass of all elements present in the compound
• Formula units are not actual amounts, but theoretical values based on data from experiment and/or calculations
• These are typically represented as a number, such as 33.64%, to indicate that one part of the compound is thirty-three point six four percent hydrogen by mass
• This contrasts with a concrete amount, like 33.64 grams or 3.364×106 molecules per second, which would be represented as a percentage by multiplying by 100 and adding % at the end (33.64 g % or 3.364×106 molecules-1 %)
• Chemical compounds can be described in several ways, including molecular formula and percent composition
• The molecular formula of a compound is the simplest way to express its chemical makeup
• The empirical formula of a chemical compound is the simplest way to express its chemical makeup if the chemical formula yields more than one molecule
• Percent composition refers to how much of each element is present in a sample of an element or compound
• Percent by mass and percent by mole are used in different calculations. When examined together, these values provide other useful information about compounds

Conclusion 

Percentage composition can be taken into account to solve several questions related to percent by mass and percentage composition of a compound. Moreover, the percent composition formula plays a big part as it helps us to find the percentage composition of a compound in a given question.