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  3. BCECE Medical

BCECE Medical BCECE Medical Solved Papers-2002

  • question_answer
    A \[CaC{{O}_{3}}\] sample contains \[3.01\times {{10}^{23}}\] ions of \[\overset{2+}{\mathop{Ca}}\,\] and \[C{{O}_{3}}^{2-}\]. The mass of sample is:

    A)  40              

    B)  50

    C)  60             

    D)  70

    Correct Answer: B

    Solution :

    Key Idea: Moles \[=\frac{Mass}{Molecular\text{ }mass}\] Or           Mass = Moles \[\times \] molecular mass Molecular mass of \[CaC{{O}_{3}}\]   \[40+12+16\times 3=40+12+48=100\] Moles of \[CaC{{O}_{3}}=\frac{3.01\times {{10}^{23}}}{6.023\times {{10}^{23}}}=0.5\] Mass of a \[CaC{{O}_{3}}=0.5\times 100=50\,\,g\]


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