Percentage Composition-Solved Examples-Class 11 Chemistry Notes Study Material

Different constituent elements make up any chemical compound. In some chemical reaction calculations, you’ll need to figure out how much of a certain element is in a specific compound. Or, in order to understand the contribution of a specific element in any of the stoichiometric calculations of a chemical compound in which the element is present, the amount of the element in the molecule must be known.

This can be determined by using the percent composition formula to get the element’s percentage composition in a particular compound.

Any compound’s percent composition expresses its composition in terms of all of the elements present. As a result, it helps in the chemical characterization of a particular compound.

What is Percentage Composition?

The percentage composition of any given compound is defined as the ratio of the amount of each element to the total amount of all individual elements that are available in the given compound and then multiplied by 100. 

In this, we measure the quantity of the elements in terms of grams which is present in the solution. This calculation is mostly used in the chemical analysis of the compound.

Formula Percentage Composition 

We can express the percentage composition of a given element using the formula below:

%CE = (gE/gT)×100

where 

  • % CE is the percentage composition of element E. 
  • gE is the total amount of element E present in the compound T.
  • gT is the total amount of all the elements present in the compound T.

Mass Percentage (w/w)%

To describe the concentration of an element in a compound or a component in a combination, we utilize the idea of mass percentage composition. The total percent by mass of each element contained in a compound is denoted by this term.

It’s important to note that the mass percentage composition can be calculated by dividing the mass of a component by the total mass of the combination. After that, multiply the ratio by 100. The mass percent (w/w)% is another name for it.

Best JEE & NEET Physics, Chemistry, Biology, and Math Study Material – Anand Classes by Neeraj Anand (Published by Anand Technical Publishers)

If you are preparing for JEE Mains, JEE Advanced, or NEET, having the right study material can make all the difference. Anand Classes, authored by Neeraj Anand and published by Anand Technical Publishers, provides one of the most comprehensive, structured, and exam-oriented study materials for Physics, Chemistry, Biology, and Mathematics Subjects according to latest trends of JEE & NEET Entrance Exams.

Why Choose Anand Classes Study Material for JEE & NEET Preparation?

The study materials by Neeraj Anand are designed to simplify complex concepts, provide in-depth explanations, and offer ample practice questions to help students achieve top scores in competitive exams.

Comprehensive Coverage – Detailed explanations of Physics, Chemistry, Biology, and Mathematics concepts.
JEE & NEET Focused – Designed specifically for competitive exam success.
Solved Examples & Practice Questions – Strengthen your understanding with concept-based problems.
Short Tricks & Formulas – Easy-to-remember techniques for quick problem-solving.
Concept Clarity: Easy-to-understand theory with step-by-step explanations.
Topic-Wise Breakdown: Well-structured chapters following the latest syllabus of JEE Mains, JEE Advanced, and NEET.
Solved Examples & Practice Questions: Includes previous year questions (PYQs), important formulas, and shortcut techniques.
NCERT-Based & Advanced Level: Covers both board exam preparation and entrance exam syllabus for JEE & NEET aspirants.
Time-Saving Tricks: Quick formulas, memory techniques, and problem-solving strategies.

📚 Subjects Covered in Anand Classes Study Material

🔵 Physics (For JEE & NEET)

  • Kinematics & Laws of Motion
  • Work, Power & Energy
  • Gravitation & Fluid Mechanics
  • Thermodynamics & Heat Transfer
  • Electrostatics & Magnetism
  • Optics & Modern Physics
  • Semiconductor Electronics & Communication

🟠 Chemistry (For JEE & NEET)

Physical Chemistry

  • Mole Concept & Stoichiometry
  • Thermodynamics & Chemical Equilibrium
  • Electrochemistry & Chemical Kinetics

Inorganic Chemistry

  • Periodic Table & Chemical Bonding
  • Coordination Compounds & Metallurgy
  • P-Block, D-Block & F-Block Elements

Organic Chemistry

  • Hydrocarbons & Functional Groups
  • Reaction Mechanisms & Named Reactions
  • Biomolecules & Polymers

🟢 Biology (For NEET)

  • Diversity in the Living World
  • Cell Structure & Function
  • Genetics & Evolution
  • Human Physiology & Reproduction
  • Ecology & Environment

🔴 Mathematics (For JEE Mains & Advanced)

Permutation, Combination & Complex Numbers

Algebra & Probability

Trigonometry & Coordinate Geometry

Calculus (Differential & Integral)

Vectors & 3D Geometry

📥 Download PDF & Purchase the Study Material

The Anand Classes Study Material is available in PDF format and hardcopy. You can access high-quality notes, question banks, and practice tests to boost your JEE & NEET preparation.

🔹 Download Now: Get the latest edition PDF for easy access on mobile, tablet, or laptop.
🔹 Buy Hardcopy: Order the printed book for detailed study and offline preparation.

📌 Published by: Anand Technical Publishers
📌 Author: Neeraj Anand


It’s important to note that the mass percentage composition can be calculated by dividing the mass of a component by the total mass of the combination. After that, multiply the ratio by 100. The mass percent (w/w)% is another name for it.

Sample Questions

Question 1: Calculate the percent composition of each element in water.

Solution:

The chemical formula of water is H2O. It contains 2 mole of Hydrogen and 1 mole of oxygen.

1 mole of Oxygen has molar mass of 16 g/mole.

1 × 16= 16 grams.

1 mole of Hydrogen has molar mass of 1.0108 g/mol.

1.008× 2 = 2.016 grams.

Total molar mass of H2O = 16+2.016 = 18.016 g/mol.

Formula of percentage composition,

%CE = (gE/gT)×100

Percentage composition of Hydrogen = (2.0016/18.016 )*100 = 11.19%

Percentage composition of oxygen = (16/18.016)*100 = 88.81%

Therefore, the percentage composition of hydrogen is 11.19% and oxygen is 88.81%.

Question 2: Calculate the Percentage composition of Carbon and Oxygen present in Glucose.

Solution:

The chemical formula of Glucose is C6H12O6.It contains 6 molecules of carbon, 12 molecules of hydrogen and 6 molecules of oxygen.

1  mole of carbon has molar mass of 12.01grams.

6 × 12.01= 72.06 grams.

1 mole of hydrogen has molar mass of 1.008 grams.

12 × 1.008 = 12.096 grams.

1 mole of oxygen has molar mass of 16grams.

6 × 16= 96 grams

Total molar mass of glucose = 72.06+12.096+96 = 180.16 g/mol.

Formula of percentage composition,

%CE = (gE/gT) × 100

Percentage composition of Carbon =(72.06/180.16) ×100 = 40%

Percentage composition of oxygen = (96/180.16) × 100 = 53.29%

Therefore, the percentage composition of carbon is 40% and oxygen is 53.29%.

Question 3: Calculate the percentage composition of all elements present in Calcium Hydroxide.

Solution:

The chemical formula of Calcium Hydroxide is Ca(OH)2.It contains 1 molecules of calcium, 2 molecules of hydrogen and 2 molecules of oxygen.

1  mole of calcium has molar mass of 40.01grams

1 × 40.01= 40.01 grams.

1 mole of hydrogen has molar mass of 1.008 grams.

2 × 1.008 = 2.016 grams.

1 mole of oxygen has molar mass of 16grams.

2 × 16= 32 grams.

Total molar mass of Calcium Hydroxide = 40.01+2.0016+32 = 74.102 g/mol.

Formula of Percentage composition,

%CE = (gE/gT)×100

Percentage composition of Calcium =(40.01/74.102)×100 = 54.12%

Percentage composition of oxygen  = (32/74.102) × 100 = 43.2%

Percentage composition of hydrogen  = (2.0016/74.102) × 100= 2.7%

Therefore, the percentage composition of calcium is 54.12%, oxygen is 43.2% and hydrogen is 2.7%.

Question 4: Calculate the percentage composition of nitrogen present in nitric acid.

Solution:

The chemical formula of nitric acid  is HNO3. It contains 1 molecules of hydrogen, 1 molecules of nitrogen and 3 molecules of oxygen.

1 mole of hydrogen has molar mass of 1.008 grams.

1 × 1.008 = 1.008 grams.

1  mole of nitrogen has molar mass of 14.01grams.

1 × 1401= 14.01 grams.

1 mole of oxygen has molar mass of 16 grams

3 × 16= 48grams.

Total molar mass of nitric acid = 14.01+1.008+48 = 63.02 g/mol.

Formula of percentage composition,

%CE = (gE/gT)×100

Percentage composition of nitrogen =(14.01/63.02) ×100 = 22.23%.

Therefore, the percentage composition of nitrogen is 22.23%.

Question 5: Calculate the Percentage composition of potassium present in potassium permanganate .

Solution:

The chemical formula of potassium permanganate is KMnO4. It contains 1 molecules of hydrogen, 1 molecules of nitrogen and 3 molecules of oxygen.

1 mole of hydrogen has molar mass of 1.008 grams.

1 × 1.008 = 1.008 grams.

1  mole of nitrogen has molar mass of 14.01grams

1 × 14.01= 14.01 grams.

1 mole of oxygen has molar mass of 16grams.

3 × 16= 48grams.

Total molar mass of nitric acid = 14.01+1.008+48 = 63.02 g/mol.

Formula of percentage composition,

%CE = (gE/gT)×100

Percentage composition of nitrogen =(14.01/63.02) × 100 = 22.23%

Therefore, the percentage composition of nitrogen is 22.23%.

Question 6: Calculate the Percentage composition of Chlorine present in Hydrochloric acid.

Solution:

The chemical formula of Hydrochloric acid  is HCl. It contains 1 molecules of hydrogen and 1 molecules of chlorine.

1 mole of hydrogen has molar mass of 1.008 grams.

1 × 1.008 = 1.008 grams.

1  mole of chlorine has molar mass of 35.45 grams.

1 × 35.45 = 35.45 grams.

Total molar mass of hydrochloric acid = 1.008+35.45 = 36.458 g/mol.

Formula of Percentage composition,

%CE = (gE/gT)×100

Percentage composition of chlorine = (35.45/36.458)×100 = 97.23%

Therefore, the percentage composition of chlorine is 97.23%.

Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.