CBSE Class 9 Science Lab Worksheet law of Conservation of Mass

Download Class 9 Science Worksheets for Conservation of Mass

Access printable practice worksheets for Conservation of Mass designed to align with the 2026-27 academic syllabus for Class 9 Science. These structured exercises help students evaluate their conceptual understanding and improve exam readiness.

Access Conservation of Mass Questions and Exercises

Navigate directly to the printable exercises for Conservation of Mass using the digital viewer below. Each practice set allows students to isolate specific topics for thorough review and uninterrupted practice alongside standard textbooks.

 
LAB SHEET

LAW OF CONSERVATION OF MASS
 
 
Objective: To prove the law of conservation of mass in a chemical reaction.
 
Requirements: Conical flask ,test tubes ,barium chloride, sodium sulphate , cork , spring balance

Theory :
 
• According to law of conservation of mass, mass can neither be created nor destroyed in a chemical reaction.
 
• Total mass of reactants = Total mass of the products

Procedure:
 
• Prepare 5% solutions of barium chloride and sodium sulphate.
 
• Take 2ml of barium chloride solution in the conical flask and 2ml of sodium sulphate solution in the test tube.
 
• Suspend the test tube with sodium sulphate in the flask with the thread and cork as shown in the figure
CBSE Class 9 Science Lab Worksheet law of Conservation of Mass 1
 
• Weigh the complete system.
 
• Now loosen the cork so that the solution in the test tube mixes with the solution in the conical flask.
 
• Again weigh the complete system.
 
• Find the difference between the initial and final masses of the system.

Observation:
 
• A white precipitate of barium sulphate is formed on mixing barium chloride and sodium sulphate which shows the formation of the product.
 
• The mass of the reaction flask is found to remain unchanged, ie, mass remains same before and after the reaction.
 
Conclusions:
 
The above activity shows that in any chemical reaction, the total mass of the reactants is equal to the total mass of the products i.e; mass can neither be created nor be destroyed in a chemical reaction which proves the law of conservation of mass.
 
Precautions
 
1. The spring balance should be held vertical while in use.
 
2. Before making use of the spring balance it must be ensured that its pointer is at zero mark
 
3. The reading of the balance should be noted only when its pointer comes to rest.
 
4. Solutions should not get mixed before initial weighing

MULTIPLE CHOICE TYPE QUESTIONS
 
1. To identify the law of conservation of mass, a student added 10 mL of 5% barium chloride solution into 10 mL of 5% sodium sulphate solution. Which one of the following is the correct observation?
 
a) A clear solution is obtained
 
b) The solution turns to red colour
 
c) A yellow precipitate is formed
 
d) A white precipitate is formed
 
2. While veryfying the law of conservation of mass Smith added 3.5 g of magnesium metal into 13.7 g of hydrochloric acid. If the mass of magnesium chloride formed is 13.8 g , what is the mass of eliminated hydrogen gas if the law of conservation of mass of mass is correct.
 
a) 3.2 g     b) 3.4 g     c) 4.3 g      d) 5 g
 
3. In a chemical reaction one molecule of nitrogen reacts with three molecules of hydrogen to form ammonia. If the law of conservation of mass is correct what will be the number of atoms of nitrogen and hydrogen at the end of the reaction?
 
a) N = 2 , H = 6
 
b) N = 1 , H = 3
 
c) N = 6 , H = 2
 
d) N = 3 , H = 3
 
4. While verifying the law of conservation of mass, a student added 5 g of sodium bicarbonate to a test tube containing 14.5 g of acetic acid. The total mass of the reactant is 19.5 g but the mass of the product after the reaction is only 16.2 g. The reduction in the mass of the product is due to
 
a) Elimination of CO2 gas
 
b) Elimination of O2 gas
 
c) Liberation of heat
 
d) Elimination of CO gas
 
5. Which one of the following reactions is not suitable in the laboratory to verify the law of conservation of mass?
 
a) Mixing HCl and NaOH solution
 
b) Thermal decomposition of ferrous sulphate
 
c) Mixing copper sulphate and barium chloride solutions
 
d) Mixing lead nitrate and potassium iodide solutions
 
6. Lime stone(CaCO3) upon strong heating undergoes thermal decomposition to form lime(CaO) and CO2 gas. The mass of CaO and mass of CO2 formed by the decomposition of 25 g of CaCO3 are (RAM of Ca = 40, C = 12 , O = 16)
 
a) CaO= 28 , CO2 = 22
 
b) CaO= 14 , CO2 = 11
 
c) CaO= 22 , CO2 = 28
 
d) CaO= 11 , CO2 = 14
 
7. To verify the law of conservation of mass, which one of the following combinations can a student select to prove the law.
 
a) Copper sulphate and sodium sulphate
 
b) Sodium sulphate and sodium chloride
 
c) Copper sulphate and sodium carbonate
 
d) Sodium sulphate and sodium carbonate
 
8. For the verification of law of conservation of mass in a chemical reaction four students, A , B, C and D performed the following reactions:
 
A - Added calcium oxide to water
 
B - Heated ferrous sulphate crystals in a test tube.
 
C - Dipped iron nails in copper sulphate solution.
 
D - Added silver nitrate to calcium chloride.
 
The student who is likely to get the best result is,
 
a) A      b) B      c) C     d) D



Please click on below link to download CBSE Class 9 Science Lab Worksheet law of Conservation of Mass

Free study material for Science

Practice Worksheet and Study Resources for Class 9 Science Conservation of Mass

Download Practice Sheet: Conservation of Mass (Class 9 Science)

Access structured practice worksheets for Conservation of Mass designed in alignment with the latest CBSE curriculum for Class 9 Science. These printable problem sets help students build accuracy and prepare effectively for school tests.

Concept Clarification for Conservation of Mass

Each worksheet is structured around standard CBSE textbooks, allowing students to check their working steps and correct mistakes early in their revision.

Additional Study Resources for Class 9 Science

Follow up your worksheet practice by attempting the interactive online Science MCQ test for this chapter to evaluate your execution speed. All platform resources are free to access.

FAQs

Where can I download the latest PDF for CBSE Class 9 Science Lab Worksheet law of Conservation of Mass?

You can download the teacher-verified PDF for CBSE Class 9 Science Lab Worksheet law of Conservation of Mass from StudiesToday.com. These practice sheets for Class 9 Science are designed as per the latest CBSE academic session.

Are these Science Class 9 worksheets based on the 2026-27 competency-based pattern?

Yes, our CBSE Class 9 Science Lab Worksheet law of Conservation of Mass includes a variety of questions like Case-based studies, Assertion-Reasoning, and MCQs as per the 50% competency-based weightage in the latest curriculum for Class 9.

Do you provide solved answers for CBSE Class 9 Science Lab Worksheet law of Conservation of Mass?

Yes, we have provided detailed solutions for CBSE Class 9 Science Lab Worksheet law of Conservation of Mass to help Class 9 and follow the official CBSE marking scheme.

How does solving CBSE Class 9 Science Lab Worksheet law of Conservation of Mass help in exam preparation?

Daily practice with these Science worksheets helps in identifying understanding gaps. It also improves question solving speed and ensures that Class 9 students get more marks in CBSE exams.

Is there any charge for the Class 9 Science practice test papers?

All our Class 9 Science practice test papers and worksheets are available for free download in mobile-friendly PDF format. You can access CBSE Class 9 Science Lab Worksheet law of Conservation of Mass without any registration.