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9th Class Science Atoms and Molecules Question Bank Atoms and Molecules

  • question_answer
    What weight of sodium contains the same number of atoms as those in \[8\] grams of oxygen?

    A) \[10.5\,\,g\]       

    B)        \[13.5\,\,g\]

    C) \[11.5\,\,g\]         

    D)        \[14.2\,\,g\]

    Correct Answer: C

    Solution :

     Gram atomic weight of sodium \[(Na)\] is\[23\,\,g\] and that of oxygen \[(O)\] is\[16\,\,g\] Number of moles of oxygen\[=\]\[\frac{\text{Weight}\,\,\text{(given)}}{\text{GAW}}=\frac{8}{16}\] Weight of sodium \[(Na)=\] Number of moles\[\times \,\,GAW=0.5\times 3=11.5\,\,g\]


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