MEDIUM
9th CBSE
IMPORTANT
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A mole of atoms of any element has a mass in grams equal to its atomic mass.

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Important Questions on Atoms and Molecules

EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
In a chemical compound, the constituent elements are present in definite proportion by mass.
MEDIUM
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
The mass of a single molecule of water is 2.99×10-23g.
MEDIUM
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
The ratio by mass of the elements present in a molecule of phosphorus pentachloride (PCI5) is 31 :177.5.
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
According to the law of conservation of mass, the mass of the products is equal to the mass of the reactants.
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
The law of constant proportion requires the combining elements to react only in simple mass ratio.
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
The mass of one Avogadro's number of molecules is termed as molar mass.
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q B
The relative atomic mass of an element is equal to the mass number of one of its atoms.
EASY
9th CBSE
IMPORTANT
LIVING SCIENCE CHEMISTRY 9>Chapter 3 - Atoms and Molecules>EXERCISES>Q C
The valency of an element with atomic number 2 is_____.