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The compositin of a sample of wustite isFe_(0-93)O_(1-00) , what precentage of the iron is present in the form ofFe(III) ? |
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Answer» Solution :The composition is ` Fe_(0-93)`intereadof FeO because some ` Fe^(2+)`ions have been replaced by ` Fe^(3+)`ions. Let us first calcuate the number of ` Fe^(2+) and Fe^(3+)`ions present. The FORMULA ` Fe_(0.93) O _(1.00)`implies that93 Fe ATOMS are combined with 100O - atoms. Out of 93 Fe atoms , suppose Fe atoms present as ` Fe^(3+)`= x , then`Fe^(2+) = 93 -x `, as the compoundis neutral, totalcharge on ` Fe^(2+) and Fe^(3+)`ions = total CHARGE on ` O^(2-)`ions. Thus, ` 3 xx x + 2( 9 3-x)= 2xx 100 or 3 x +1 86-2x = 200 orx=14 , i.e. Fe^(3+) =14` Hence, ` Fe^(2+) = 93 - 14=79` Thus, out of 93 Fe atoms, Fe PRESNET as ` Fe^(3+)=14 ` :% ageof Fe presnet as Fe ( III)= ` 14/93 xx 100 = 15%` |
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