can anyone help with this chemistry question? ?

A bottle of pure element was missing part of a label. The label said 2.258 x 1023 atoms. You determine the mass of the elements in the bottle to be 32.45386 g. What element is this?

2 Answers

  • 4 weeks ago
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    (32.45386 g) / (2.258 x 10^23 atoms / (6.02214 x 10^23 atoms/mol)) = 86.555 g/mol

    The element with an atomic mass like that is either Rb or Sr.  (Since it is unlikely Rb would be kept in a bottle by itself (Because it reacts with air, it usually is kept under mineral oil.) I'd choose Sr.

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  • 4 weeks ago

    LOL .... bottles are not labeled by the number of atoms. 

    molar mass = grams / mol

    molar mass = 32.45g / (2.258x10^23 atoms x (1 mol atoms / 6.022x10^23 atoms))

    molar mass = 86.54 g/mol

    There is no element with a molar mass of 86.54 g/mol.

    Rubidium .... 85.47 g/mol

    Strontium .... 87.62 g/mol

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