Class 9 Science Chapter 9: Atomic Foundations of Matter — practice questions with answers
Free practice for Class 9 Science, Chapter 9: Atomic Foundations of Matter. Try the solved questions below, then take a free test with instant marking and explanations.
54 questions12 easy, 30 medium, 12 hardNCERT · CBSE · State boards
Sample questions with solutions
Q1. What does the Law of Conservation of Mass state?
- Matter is neither created nor destroyed in a chemical reaction
- Mass always increases in a reaction
- Gases have no mass
- Mass is lost as heat
Show answer
Answer: A. Matter is neither created nor destroyed in a chemical reaction
Why: Proposed by Lavoisier in 1789. [p.165]
Why: Proposed by Lavoisier in 1789. [p.165]
Q2. 20 g of hydrogen reacts completely with 160 g of oxygen. How much water is formed (g)?
Show answer
Answer: 180 (± 0)
Why: 20 + 160 = 180 g. [p.166]
Why: 20 + 160 = 180 g. [p.166]
Q3. Find the molecular mass of carbon dioxide, CO₂ (C = 12 u, O = 16 u).
Show answer
Answer: 44 (± 0)
Why: 12 + 32 = 44 u. [p.179]
Why: 12 + 32 = 44 u. [p.179]
Q4. Which are covalent molecules? (Tick all that apply)
- H₂
- HCl
- H₂O
- NaCl
Show answer
Answer: A. H₂; B. HCl; C. H₂O
Why: NaCl is ionic. [p.169–173]
Why: NaCl is ionic. [p.169–173]
Q5. The mass of a solution equals the sum of the masses of solute and solvent.
True or false?
Show answer
Answer: True
Why: Physical changes conserve mass. [p.163]
Why: Physical changes conserve mass. [p.163]
Q6. Covalent compounds usually have low melting and boiling points.
True or false?
Show answer
Answer: True
Why: Weaker forces between molecules. [p.179]
Why: Weaker forces between molecules. [p.179]
Practise all 54 questions free
Timed test, marked instantly, with the correct answer and explanation for every question and a chapter-wise report.
Start the free testUnderstand it by doing
Try the interactive Science Lab for Class 9.
Frequently asked questions
How many practice questions are there for Class 9 Science Chapter 9: Atomic Foundations of Matter?
54 questions (12 easy, 30 medium, 12 hard). A few are solved on this page; the free test shows the answer and explanation for every question after you submit.
Is this chapter from the NCERT book?
Yes — it follows the NCERT Class 9 Science syllabus, used by CBSE and many state boards.