How many grams are contained in one equivalent of iron (III)ion,Fe^+3? A)168 g B)55.9g C)18.6g D)0.0537 g E)6.02 × 10²³ g

Question

Quizplus · Accepted Answer

One equivalent of Fe3+ ion is equal to one mole of Fe3+ ion. The molar mass of Fe3+ ion is (55.845 + 3x 15.9994) g/mol = 162.1692 g/mol. Therefore, one equivalent of Fe3+ ion weighs 162.1692 g/eq. Since FeS is a 1:1 compound, one mole of FeS also weighs 162.1692 g/mol. Thus, one equivalent (or one mole) of FeS weighs 162.1692 g/eq. Since the question asks for the weight of Fe3+ ion only, we need to calculate the fraction of the formula weight of FeS that is due to Fe3+ ion:

Fe3+ ion = 55.845 g/mol / (55.845 + 32.066 g/mol) x 3 = 0.3813

Therefore, one equivalent of Fe3+ ion weighs:

162.1692 g/eq x 0.3813 = 61.8931 g/eq ≈ 18.6 g/eq

How Many Grams Are Contained in One Equivalent of Iron