Atoms and Molecules - Set 4 | Class 9 Science MCQ Quiz

1. According to the Law of Conservation of Mass, what happens to mass during a chemical reaction?

A) It is created B) It is destroyed C) It remains unchanged D) It can be created or destroyed depending on the reaction

2. Who formulated the Law of Constant Proportions?

A) Antoine L. Lavoisier B) John Dalton C) Joseph L. Proust D) Democritus

3. What does the Law of Constant Proportions state about a pure chemical compound?

A) Elements combine in a variable ratio by mass B) Elements are always present in definite proportions by mass C) Elements can combine in any ratio by mass D) The ratio of elements changes with different samples

4. How is the atomic mass unit (u) related to the mass of an atom?

A) It is equal to the mass of a hydrogen atom B) It is one-twelfth the mass of a carbon-12 atom C) It is the mass of the most abundant isotope D) It is a relative mass compared to oxygen

5. What is meant by the "atomicity" of a molecule?

A) The number of protons in an atom B) The number of electrons in an atom C) The number of atoms constituting a molecule D) The atomic number of an element

6. An ion is formed when an atom gains or loses:

A) Protons B) Neutrons C) Electrons D) Nucleons

7. What is a polyatomic ion?

A) An ion with only one atom B) A group of atoms carrying a net charge C) An atom with a varying number of electrons D) An atom that has gained a proton

8. What is the valency of an element?

A) Its atomic number B) Its atomic mass C) Its combining power or capacity D) Its density

9. What does the chemical formula H₂SO₄ represent?

A) Two atoms of hydrogen, one atom of sulfur, four atoms of oxygen B) One molecule of hydrogen, one molecule of sulfur, four molecules of oxygen C) Two parts hydrogen, one part sulfur, four parts oxygen by mass D) A mixture of hydrogen, sulfur, and oxygen

10. What is the formula unit mass for Potassium Carbonate (K₂CO₃) given atomic masses: K=39u, C=12u, O=16u?

A) 130 u B) 138 u C) 144 u D) 152 u

Atoms and Molecules - Class 9 Science Quiz

A Quiz for CBSE Class 9 Science Students (Set 4)

1. According to the Law of Conservation of Mass, what happens to mass during a chemical reaction?

2. Who formulated the Law of Constant Proportions?

3. What does the Law of Constant Proportions state about a pure chemical compound?

4. How is the atomic mass unit (u) related to the mass of an atom?

5. What is meant by the "atomicity" of a molecule?

6. An ion is formed when an atom gains or loses:

7. What is a polyatomic ion?

8. What is the valency of an element?

9. What does the chemical formula H₂SO₄ represent?

10. What is the formula unit mass for Potassium Carbonate (K₂CO₃) given atomic masses: K=39u, C=12u, O=16u?

Quiz Results

Atoms and Molecules Quizzes

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Atoms and Molecules - Class 9 Science Quiz

A Quiz for CBSE Class 9 Science Students (Set 4)

1. According to the Law of Conservation of Mass, what happens to mass during a chemical reaction? Read

2. Who formulated the Law of Constant Proportions? Read

3. What does the Law of Constant Proportions state about a pure chemical compound? Read

4. How is the atomic mass unit (u) related to the mass of an atom? Read

5. What is meant by the "atomicity" of a molecule? Read

6. An ion is formed when an atom gains or loses: Read

7. What is a polyatomic ion? Read

8. What is the valency of an element? Read

9. What does the chemical formula H2SO4 represent? Read

10. What is the formula unit mass for Potassium Carbonate (K2CO3) given atomic masses: K=39u, C=12u, O=16u? Read

Quiz Results

Atoms and Molecules Quizzes

Was this page helpful?

1. According to the Law of Conservation of Mass, what happens to mass during a chemical reaction?

2. Who formulated the Law of Constant Proportions?

3. What does the Law of Constant Proportions state about a pure chemical compound?

4. How is the atomic mass unit (u) related to the mass of an atom?

5. What is meant by the "atomicity" of a molecule?

6. An ion is formed when an atom gains or loses:

7. What is a polyatomic ion?

8. What is the valency of an element?

9. What does the chemical formula H₂SO₄ represent?

10. What is the formula unit mass for Potassium Carbonate (K₂CO₃) given atomic masses: K=39u, C=12u, O=16u?