Gravimetric Analysis the Determination of Phosphorus in...

Gravimetric Analysis: The Determination of Phosphorus in Plant Food Gravimetric analysis is a quantitative (i.e. how much?) method of classical analysis. The element to be determined is isolated in a solid compound of known identity and definite composition. The mass of the element that was present in the original sample can be determined from the mass of this compound. Plant foods contain three essential nutrients that are not readily available from soils. These are soluble compounds of nitrogen, phosphorus, and potassium. A typical label on a plant food will have a set of numbers such as 15-30-15. These numbers mean that the plant food is guaranteed to contain at least 15% nitrogen, 30% phosphorus (expressed as P2O5) and†¦show more content†¦Record the sample mass in your notebook. Remember to record all digits on the balance. Closed toed shoes and goggles are REQUIRED for the lab 2. Add about 20 mL of distilled water and stir the mixture with a glass stirring rod to dissolve the sample. There may be a small amount of insoluble residue. If your sample does not dissolve completely, remove the insoluble material by filtration. 3. Add 25 mL of 10% MgSO4 . 7H2O solution to the filtrate. Then add approximately 75 mL of 2M NH3 slowly while stirring. A white precipitate of MgNH4PO4 . 6H2O will form. Allow the mixture to sit at room temperature for 15 minutes to complete the precipitation. 4. Prepare a vacuum filtration apparatus using a buchner funnel. Obtain one filter paper for each one of your samples, weigh them and record their mass in your notebook (label them with a pencil to be able to differentiate them later). 5. Wet the paper with distilled water to hold it in place in the funnel. Transfer all the solution and the precipitate from the beaker using a rubber policeman. Wash the precipitate with two or three 5-mL portions of distilled water. Do this by adding each portion to the beaker in which you did the precipitation to transfer any remaining precipitate; then pour over the solid in the funnel. Finally, pour two 10-mL portions of 75% isopropyl alcohol through the filter paper. 6. When all the liquid hasShow MoreRelatedGravimetric Determination of Phosphorus in Fertilizer Samples3100 Words   |  13 Pages Date Due: 18 January 2013 Date Submitted: 18 January 2013 Experiment No. 3: GRAVIMETRIC DETERMINATION OF PHOSPHORUS IN FERTILIZER SAMPLES I. Abstract The purpose of this experiment is to determinethe Phophorus content of fertilizer samples using Gravimetric Analysis. It involves dissolution of the fertilizer sample, precipitation and heating and cooling of the sample. Pooled standard deviations of the two data sets forRead MoreContamination of the Turag River19368 Words   |  78 Pagesincreasing. The water quality of Turag is deteriorating day by day. This is affecting the natural resources and is crucial for the survival for all living organisms including human, food production amp; economic development. Today there are many cities worldwide facing an acute shortage of water and nearly 40% of the world’s food supply is grown under irrigationamp; a wide variety of industrial process depends on water. The Dhaka water supply and sewage authority is entrusted with the supply of piped