1. Mass unit equal to exactly one- twelfth the mass of one atom of carbon - 12 is called one atomic mass unit. It is written as 'u'. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

    Mass unit equal to exactly one- twelfth the mass of one atom of carbon – 12 is called one atomic
    mass unit. It is written as ‘u’.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

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  2. The postulate of Dalton's atomic theory which can explain the law of definite proportion is “The relative number and kind of atoms in a given compound remains constant”. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

    The postulate of Dalton’s atomic theory which can explain the law of definite proportion is “The
    relative number and kind of atoms in a given compound remains constant”.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

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  3. The postulate of Dalton's atomic theory which is a result of the law of conservation of mass is “Atoms are indivisible particles, which can neither be created nor destroyed in a chemical reaction”. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chaptRead more

    The postulate of Dalton’s atomic theory which is a result of the law of conservation of mass is
    “Atoms are indivisible particles, which can neither be created nor destroyed in a chemical
    reaction”.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

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  4. It is given that the ratio of hydrogen and oxygen by mass to form water is 1:8. Then, the mass of oxygen gas required to react completely with 1g of hydrogen gas is 8g. Therefore, the mass of oxygen gas required to react completely with 3g of hydrogen gas is 8 × 3g = 24 g. For more answers visit toRead more

    It is given that the ratio of hydrogen and oxygen by mass to form water is 1:8. Then, the mass of
    oxygen gas required to react completely with 1g of hydrogen gas is 8g. Therefore, the mass of
    oxygen gas required to react completely with 3g of hydrogen gas is 8 × 3g = 24 g.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

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  5. In a reaction, sodium carbonate reacts with ethanoic acid to produce sodium ethanoate, carbondioxide, and water. Sodium + Ethanoic → Sodium + Carbon + Water Carbonate acid ethanoate dioxide Mass of sodium carbonate = 5.3g (Given) Mass of ethanoic acid = 6g (Given) Mass of sodium ethanoate = 8.2g (GiRead more

    In a reaction, sodium carbonate reacts with ethanoic acid to produce sodium ethanoate,
    carbondioxide, and water.

    Sodium + Ethanoic → Sodium + Carbon + Water
    Carbonate acid ethanoate dioxide

    Mass of sodium carbonate = 5.3g (Given)
    Mass of ethanoic acid = 6g (Given)
    Mass of sodium ethanoate = 8.2g (Given)
    Mass of carbon dioxide = 2.2 (Given)
    Mass of water = 0.9g (Given)

    Now, total mass before the reaction = (5.3 + 6)g
    = 11. 3g
    and total mass after the reaction = (8.2 + 2.2 + 0.9)g
    = 11.3g
    Therefore, Total mass before the reaction = Total mass after the reaction
    Hence, the given observations are in agreement with the law of conservation of mass.

    For more answers visit to website:
    https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-3/

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