?GRAVIMETRIC ANALYSIS EQUIPMENT NEEDED 50 mL beaker 10 mL graduated cylinder 250 mL suction flask Buchner funnel Watch glass Red litmus paper Filter paper Graduated disposable pipet Vacuum tubing Funnel CHEMICALS NEEDED 0.4M MgSO4 solution 6M NH3 Fertilizer (Miracle Grow) PROCEDURE Note: Each person in the pair does the experiment on his or her own. Therefore, there should be a total of four trials, two from each person in the pair. 1. Weigh out 0.55 ± 0.01 grams of fertilizer sample using an analytical balance to assure accurate measurements. 2. Dissolve the fertilizer sample in 10 mL deionized water in a 50mL beaker. 3. Once dissolved, filter the solution through a funnel lined with a wet filter paper to rid the solution of insoluble components that are present in the fertilizer (insoluble components will alter the final weight measurement of the precipitate as they will not filter through the Buchner funnel. Additionally, insoluble components will not react in the precipitate and therefore have little use in the experiment). Be sure to add a little water to the filter to ensure that all of the fertilizer solution has been filtered through. 4. To the filtered fertilizer solution, add 10mL of 0.4M MgSO4 solution. 5. Using a disposable pipet, slowly add 1mL of 6M NH3 dropwise while stirring. Dropwise addition of NH3 will ensure that just enough NH3 is added to the solution that it reacts completely with the MgSO4 and fertilizer. It limits excess addition of NH3. 6. After adding all of the NH3, touch the stirring rod to a piece of red litmus paper. If the paper does not turn blue, add 0.5mL more of NH3 dropwise at a time. Between each dose of 5mL NH3, touch the litmus paper. Once the paper turns blue, add a few more drops to ensure that all of the fertilizer, MgSO4, and NH3 have reacted with one another. This will allow the fertilizer, MgSO4, and NH3 to form the precipitate insoluble Mg(NH4)PO4?H2O. 7. Let the solution stand 15 min