Physical Chemistry - Lab Report Example

For example, steel containing a higher percentage of Mn is suitable for production of complex tools and durable machine parts. Contrarily, steel containing a substantial percentage of chromium is used to produce metallic parts that resist corrosion. In this case, quantitative determination of transition elements in steel is significant in industrial chemistry. Primarily, steel is made up of iron but it contain trace amounts of transition metals like manganese, chromium and copper among others.

In practice, the actual amount of each element in a steel alloy can be determined quantitatively. This lab exercise covered on quantitative determination of manganese Mn in an unknown sample of steel. Determination of Mn in steel took advantage of the selective oxidation process underwent by Mn ions when exposed to a strong oxidizing agent like sodium bismuthate. In theory, colorless Mn ions in steel change to the deep purple MnO4- ions which can be quantitatively determined using the visible spectroscopy technique.

In addition, back titration of Mn ions with agents like Fe2+ allows quantitative determination of Mn in steel. In practical contexts, precise determination of Mn in steel is compromised by the interfering effect of other trace elements metals like chromium (Stoddard, 2011). However, the interfering effects of these elements can be eliminated by masking their colorful complexes with compounds like phosphoric acid which form colorless complexes with most ions. Subsequent sections of this report contain steps used in quantitative determination of Mn in steel.

The first method in quantitative determination of Mn in steel was volumetric analysis. In this method, unknown samples of steel were titrated with KMnO4 followed by back titration of the sample with ferrous ammonium sulfate. First, a standard KMnO4 was prepared by titrating 0.1 M KMnO4 with sodium oxalate. Three separate standardization