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Atoms and Molecules

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Laws of Chemical Combination

Subtopic

Laws of Chemical Combination under Atoms and Molecules for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If 12 g12\ g of Magnesium burns in Oxygen to produce 20 g20\ g of Magnesium Oxide, the mass of Oxygen used is:

    A.

    32 g32\ g

    B.

    12 g12\ g

    C.

    8 g8\ g

    D.

    20 g20\ g

  2. 2.

    Which postulate of Dalton's theory explains the Law of Constant Proportions?

    A.

    Atoms are indivisible

    B.

    Atoms of different elements have different masses

    C.

    The relative number and kinds of atoms are constant in a given compound

    D.

    Atoms cannot be created or destroyed

  3. 3.

    In Ammonia (NH3NH_3), if we have 17 g17\ g of the compound, what is the mass of Nitrogen present, given the ratio is 14:314:3?

    A.

    3 g3\ g

    B.

    14 g14\ g

    C.

    17 g17\ g

    D.

    7 g7\ g

Download the worksheet for Atoms and Molecules - Laws of Chemical Combination to practice offline. It includes additional chapter-level practice questions.

Atomic Mass

Subtopic

Atomic Mass under Atoms and Molecules for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of the following elements has the lowest atomic mass?

    A.

    Hydrogen

    B.

    Helium

    C.

    Oxygen

    D.

    Nitrogen

  2. 2.

    Which of these elements has the highest atomic mass?

    A.

    Sodium

    B.

    Calcium

    C.

    Carbon

    D.

    Lead

  3. 3.

    An atom with 2 protons and 2 neutrons has an atomic mass of:

    A.

    2 u2\ u

    B.

    4 u4\ u

    C.

    6 u6\ u

    D.

    8 u8\ u

Download the worksheet for Atoms and Molecules - Atomic Mass to practice offline. It includes additional chapter-level practice questions.

Molecules and Ions

Subtopic

Molecules and Ions under Atoms and Molecules for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Which of the following elements exists as a monoatomic molecule?

    A.

    Neon

    B.

    Oxygen

    C.

    Hydrogen

    D.

    Fluorine

  2. 2.

    The valency of the Nitride ion is:

    A.

    1

    B.

    2

    C.

    3

    D.

    4

  3. 3.

    The molecular mass of CO2CO_{2} is: (Atomic mass: C=12u,O=16uC=12u, O=16u)

    A.

    28 u

    B.

    32 u

    C.

    44 u

    D.

    56 u

Download the worksheet for Atoms and Molecules - Molecules and Ions to practice offline. It includes additional chapter-level practice questions.

Writing Chemical Formulae

Subtopic

Writing Chemical Formulae under Atoms and Molecules for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    What is the chemical formula for Ammonium Phosphate?

    A.

    NH4PO4NH_{4}PO_{4}

    B.

    (NH4)2PO4(NH_{4})_{2}PO_{4}

    C.

    (NH4)3PO4(NH_{4})_{3}PO_{4}

    D.

    NH4(PO4)3NH_{4}(PO_{4})_{3}

  2. 2.

    What is the valency of Silver in Silver Nitrate (AgNO3AgNO_{3})?

    A.

    1

    B.

    2

    C.

    3

    D.

    4

  3. 3.

    What is the chemical formula for Lead(II) Chloride?

    A.

    PbClPbCl

    B.

    PbCl2PbCl_{2}

    C.

    Pb2ClPb_{2}Cl

    D.

    Pb2Cl2Pb_{2}Cl_{2}

Download the worksheet for Atoms and Molecules - Writing Chemical Formulae to practice offline. It includes additional chapter-level practice questions.

Mole Concept

Subtopic

Mole Concept under Atoms and Molecules for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    One mole of Magnesium atoms (MgMg) and one mole of Iron atoms (FeFe) have the same:

    A.

    Mass

    B.

    Number of atoms

    C.

    Density

    D.

    Volume

  2. 2.

    What is the mass of 11 mole of Aluminium (AlAl)? (Atomic mass of Al=27 uAl = 27\ u)

    A.

    13 g13\ g

    B.

    27 g27\ g

    C.

    54 g54\ g

    D.

    27 u27\ u

  3. 3.

    How many moles are in 22 g22\ g of Carbon dioxide (CO2CO_2)? (Molar mass of CO2=44 g/molCO_2 = 44\ g/mol)

    A.

    22 moles

    B.

    0.50.5 mole

    C.

    11 mole

    D.

    0.250.25 mole

Download the worksheet for Atoms and Molecules - Mole Concept to practice offline. It includes additional chapter-level practice questions.

Atoms and Molecules - Class 9 Science (CBSE) | Krit.club