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Grade 11Physical Chemistry

Average atomic mass of magnesium is 24.31a.m.u.this magnesium ia composed of 79mole % of magnesium 24 and remaining 21mole % of magnesium 25 and 26.calculate mole % of magnesium 26.

Profile image of anjali
9 Years agoGrade 11
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1 Answer

Profile image of Vikas TU
9 Years ago
Avg. at. mass => 24.31 = [(0.79)(24) + x(25) + (21 – x)(26)]/100
On solving for x we get,
2431 = (18.96 + 25x + 546 – 26x)
1886 = -x
or x% = > 18.86
for 26 it is => (21 – 18.86) => 2.14%