Submitted by: -------------------
Date of Submission: 27.03.11
Objectives:
In steel production aside the iron, which is the primary source, some amounts of manganese is used together with carbon. The objective of this experiment is determining the manganese amount in the steel compound by using UNICAM UV-VIS Spectrometer.
Theory:
Many molecules absorb ultraviolet or visible light. The absorbance of a solution increases as attenuation of the beam increases. Absorbance is directly proportional to the path length, b, and the concentration, c, of the absorbing species. Beer's Law states that
A = ebc, where e is a constant of proportionality, called the absorptivity.
Different molecules absorb radiation of different wavelengths. An absorption spectrum will show a number of absorption bands corresponding to structural groups within the molecule.
In this experiment wavelength range between 400-650nm is used in order to detect in the visible range.
Steel is an alloy primarily composed of iron with carbon content between 0.02% and 1.7% by weight. 1.5% manganese is may be used too, to provide additional strength for a modest price increase. Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another. Manganese is essential to iron and steel production by virtue of its sulfur-fixing, deoxidizing, and alloying properties.
In order to detect the manganese amount in the compound KIO4 is used to oxidize Mn+2 to Mn +7 since Mn+2 does not absorb in the visible region therefor cannot be detected.
Tungsten lamp is used in the experiment to reach the range between 400-650nm. After the beam comes from the tungsten lamp, it passes through the monocromator to reach the wavelength range which was selected to find the maximum wavelength. After the light passes through the monocromator it goes through the cuvette and then