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

  • question_answer
    Calculate the number of atoms present in \[71\,\,g\] of\[C{{l}_{2}}\].

    A) \[1.205\times {{10}^{-24}}\]atoms        

    B) \[1.205\times {{10}^{23}}\]atoms

    C) \[1.205\times {{10}^{24}}\]atoms  

    D)        \[1.205\times {{10}^{-23}}\]atoms

    Correct Answer: C

    Solution :

     Number of atoms \[=\] Number of gram atoms \[\times \]Avogadro's number. Atomic weight of\[Cl=35.5\] Number of atoms of\[Cl=\]             \[=\frac{71.00}{35.50}\times 6.023\times {{10}^{23}}\]             \[=2\times 6.023\times {{10}^{23}}=1.025\times {{10}^{24}}\]


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