Solution:
a. Assume 100 g of sample:
"56g C\u00d7(1mol C)\/(12.01115g C)" = 4.66 mol C
"18g H\u00d7(1mol H)\/(1.00797g H)" = 17.86 mol H
"32g O\u00d7(1mol O)\/(15.99491g O)" = 2.00 mol O
Since atoms combine in the same ratio that moles do, we divide all of the numbers of moles by the
smallest number to put everything into lowest terms:
C4.66 H17.86 O2.00 → C4.66/2.00 H17.86/2.00 O2.00/2.00 → C2.33 H8.93 O1.00
If the mole ratio is not all whole numbers, we multiply through by the smallest integer which will
turn all of the numbers into integers. These numbers are the subscripts of the elements in the empirical
formula.
(C2.33 H8.93 O1.00)3 = C7 H27 O3 (empirical formula)
Answer: C7 H27 O3 (empirical formula)
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