"I believe that www.coursework.info provides a resource which most students would find highly beneficial."
To find out the dissolved oxygen in a water sample
- Words:
- 421
- Submitted:
- Thu Nov 05 2009
- Mark submitted by Author:


... Experiment 9 Aim To find out the dissolved oxygen in a water sample. Procedure 1. A water sample was collected by a 250cm3 volumetric flask. The flask was filled completely with water without trapping any air bubbles. 2. 1 cm3 of manganese(II) sulphate solution was added to the sample using a pipette. The solution was discharged well below the surface. 3. 1 cm3 of alkaline potassium iodide solution was introduced similarly. It was sure that no air becomes entrapped. The bottle was inverted to distribute the precipitate uniformly. 4. When the precipitate has settled at least 3 cm below the stopper, 1 cm3 of concentrated sulphuric(VI) acid was introduced well below the surface. The stopper was replaced and carefully mixed until the precipitate disappears. A magnetic stirrer was used. 5. The mixture was allowed to stand for 5 min and then 100 cm3 of the acidified sample was withdrawn into a 250 cm3 conical flask. 6. 0.0125M sodium thiosulphate














