Concept explainers
A 0.450-g sample of steel contains manganese as an impurity. The sample is dissolved in acidic solution and the manganese is oxidized to the permanganate ion
Interpretation:
The mass by percent of manganese in the sample is to be calculated with given mass, volume, and concentration.
Concept introduction:
The reactions in which one reactant gets oxidized while the other gets reduced are called oxidation-reduction reactions or redox reactions.
In an acidic solution, permanganate (VII) is reduced to the colorless
The original amount of iron (II) is calculated as:
The excess iron (II) is calculated as:
The amount of iron(II) consumed is calculated as:
The mass of manganese is calculated as:
The mass percent of Mn is calculated as:
Answer to Problem 62AP
Solution:
Explanation of Solution
Given information: A
sample of steel contains manganese as an impurity. The permanganate ion is reduced to
by
of
The balanced equation for the permanganate iron (II) reaction is represented below.
Thus, one mole of permanganate is stoichiometrically equivalent to five moles of iron(II).
The original amount of iron(II) is calculated as follows.
The excess amount of iron (II) is determined by using the balanced equation represented below.
Thus, one mole of dichromate is equivalent to six moles of iron (II).
The excess iron (II) is calculated as follows:
The amount of iron(II) consumed is calculated as follows:
The mass of manganese is calculated as follows:
Finally, the mass by mass percent of Mn is calculated as follows:
The mass by percent of manganese is calculated to be
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Chapter 23 Solutions
EBK CHEMISTRY
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