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

  • question_answer
    Calculate the number of molecules present in\[0.5\]moles of magnesium oxide\[(MgO)\]. (Atomic weights\[Mg=24,\,\,O=16\])

    A)  \[14.09\times {{10}^{23}}\]molecules

    B)  \[3.0115\times {{10}^{23}}\]molecules  

    C)  \[30.12\times {{10}^{23}}\]molecules

    D)  \[14.09\times {{10}^{-23}}\]molecules

    Correct Answer: B

    Solution :

     Number of molecules of\[MgO\]\[=0.5\times 6.023\times {{10}^{23}}=3.0115\times {{10}^{23}}\]


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