1. Phosphates CE 370 - Lab

2. What is Phosphate Phosphate is a salt of phosphoric acid. Phosphates are also important in biochemistry and biogeochemistry. This is a 3-D Model the phosphate anion, PO 4 3−

3. Chemical Properties The phosphate ion is a polyatomic ion with the empirical formula PO 4 3− and a molar mass of 94.973 g/mol. The phosphate ion is a polyatomic ion with the empirical formula PO 4 3− and a molar mass of 94.973 g/mol. It consists of one central phosphorus atom surrounded by four identical oxygen atoms. It consists of one central phosphorus atom surrounded by four identical oxygen atoms. The phosphate ion carries a negative three formal charge and is the conjugate base of the hydrogenphosphate ion, HPO 4 2−, which is the conjugate base of H 2 PO 4 −, the dihydrogen phosphate ion, which in turn is the conjugate base of H 3 PO 4, phosphoric acid. The phosphate ion carries a negative three formal charge and is the conjugate base of the hydrogenphosphate ion, HPO 4 2−, which is the conjugate base of H 2 PO 4 −, the dihydrogen phosphate ion, which in turn is the conjugate base of H 3 PO 4, phosphoric acid.

4. Occurrence Phosphates are the naturally occurring form of the element phosphorus, found in many phosphate minerals. Elemental phosphorus and phosphides are not found (rare phosphide minerals may be found in meteorites). In mineralogy and geology, phosphate refers to a rock or ore containing phosphate ions.

5. Uses Phosphates are often used in laundry detergent as a water softener, but, because of algae boom-bust cycles tied to emission of phosphates into watersheds, phosphate detergent sale or usage is restricted in some areas. Phosphates are often used in laundry detergent as a water softener, but, because of algae boom-bust cycles tied to emission of phosphates into watersheds, phosphate detergent sale or usage is restricted in some areas. In agriculture phosphate refers to one of the three primary plant nutrients, and it is a component of fertilizers In agriculture phosphate refers to one of the three primary plant nutrients, and it is a component of fertilizersagricultureplant fertilizersagricultureplant fertilizers Phosphates are used as ingredients in baking powders, toothpastes, cured meats, evaporated milk, soft drinks, processed cheeses, pharmaceuticals, and water softeners. Phosphates are used as ingredients in baking powders, toothpastes, cured meats, evaporated milk, soft drinks, processed cheeses, pharmaceuticals, and water softeners.

6. Problem Nutrients such as nitrogen, phosphorus, carbon, and silicon are essential for algae to grow. Water bodies provide an important environment for the growth of algae that provides a rich food source for fish and other animals in the aquatic food chain. These nutrients find their way into the waterways through agricultural runoff, soil erosion, and discharges from the treatment of human waste. While nutrient enrichment is a natural process, too much enrichment can cause algae to grow uncontrollably, disturbing the balance among organisms in the food chain. Fortunately, these aquatic environments are very resilient and this over-enrichment, or eutrophication, can be managed.

7. Objective The objective of the experiment is to determine PO4 (phosphate) in water and wastewater.

8. Reagents Stock Solution Stock Solution Standard Solution Standard Solution 5 N Sulfuric Acid 5 N Sulfuric Acid Potassium antimonyl tartarate Potassium antimonyl tartarate 4% Ammonium Molybdate 4% Ammonium Molybdate Ascorbic Acid Ascorbic Acid Combined Reagent Combined Reagent

9. Procedure Take 25 ml sample in a 50-ml graduated tube Take 25 ml sample in a 50-ml graduated tube Add 4 ml combined reagent. Add 4 ml combined reagent. Cover the tube with parafilm and shake well. Cover the tube with parafilm and shake well. Wait for blue color to develop. It needs 10-30 minutes time. Wait for blue color to develop. It needs 10-30 minutes time. Measure absorbance on the Spectronic-21 at the wavelength 880 nm. Measure absorbance on the Spectronic-21 at the wavelength 880 nm.