Question

The average atomic mass of a sample of an element X is 16.44. What are the percentages of isotopes 16 8X & 18 8X in the sample. Plzz answer fast

Answer 1

Hi friend ✋✋✋✋
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Your answer
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Let the percentage of 16 8X isotope be y% .Then, percentage of 18 8X isotope will be (100 - y)%.

Now,
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$\frac{16 \times y}{100} + \frac{18 \times (100 - y)}{100} =16.44 \\ \\ = > \frac{16y}{100} + \frac{(1800 - 18y)}{100} = 16.44 \\ \\ = > \frac{(16y + 1800 - 18y)}{100} = 16.44 \\ \\ = > - 2y + 1800 = 16.44 \times 100 \\ \\ = > - 2y = 1644 - 1800 \\ \\ = > - 2y = - 156 \\ \\ = > 2y = 156 \\ \\ = > y = \frac{156}{2} \\ \\ = > y = 78\%$
Thus, percentage of 16 8X isotope = y = 78%

Percentage of 18 8X isotope = (100 - y)% = (100 - 78)% = 22%

HOPE IT HELPS