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Class 9 Atomic Foundations of Matter worksheet
CBSE Science. Symbols, laws of chemical combination, molecular mass, ions and formulas. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The symbol of nitrogen is:
- N
- He
- Au
- Fe
Answer
(a) N
- 2.
The atomicity of S₈ is:
- diatomic
- triatomic
- polyatomic (8 atoms)
- tetra-atomic
Answer
(c) polyatomic (8 atoms)
- 3.
The law of conservation of mass says that in a chemical reaction:
- mass always decreases
- only gases have mass
- mass always increases
- mass can neither be created nor destroyed
Answer
(d) mass can neither be created nor destroyed
Section B · short answer
- 4.
Write the chemical formulas of (a) zinc sulphide and (b) copper nitrate.
Answer
(a) ZnS; (b) Cu(NO₃)₂
balance the valencies
- 5.
In hydrogen sulphide, hydrogen and sulphur combine in the ratio 1 : 16 by mass. How much sulphur combines with 19 g of hydrogen? What mass of hydrogen sulphide forms?
Answer
304 g of sulphur; 323 g of hydrogen sulphide
19 × 16 ÷ 1; conservation of mass
Section C · long answer
- 6.
State the postulates of Dalton's atomic theory.
Answer
All matter is made of tiny particles called atoms. Atoms are indivisible and cannot be created or destroyed in a chemical reaction. Atoms of an element are identical in mass and properties; atoms of different elements differ. Atoms combine in small whole-number ratios to form compounds. The relative number and kinds of atoms are constant in a given compound.
Fresh sheets for your child
In the app, every Atomic Foundations of Matter sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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