Relative atomic mass?

Anyone knows how to solve this question? 

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  • Adam
    Lv 7
    3 months ago
    Favorite Answer

    Let y% be the percent abundance of ³⁰Si.

    Then, the percent abundance of ²⁹Si = (100 - 92.2 - y)% = (7.8 - y)%

    Relative atomic mass of Si:

    28.0 × 92.2% + 29.0 × (7.8 - y)% + 30.0 × y% = 28.09

    2581.6 + 226.2 - 29.0y + 30.0y = 2809

    y = 1.2

    Hence, the percent abundance of ³⁰Si = 1.2%

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