Analysis of the Nitrogen Content of Lawn Fertiliser Essay

Research Question What is the fortune by battalion of atomic number 7 (from the ammonium ion ion ion ion NH4+) in Bunnings Green Up disgrace of lawn fertiliser compa departure to the shapers stipulation of 12.3%?Aim To determine the piece by chaw of available newton, deliver as the ammonium ion, in Bunnings Green Up brand of lawn plant food, then comparing it with the mavin qualify by the manu incidenturer.Hypothesis Since the ammonium ion (NH4+) present in plant foods is a short acid, it is hard to obtain an exact eat up point. Hence, back tit ration fecal mat upter be apply to determine the percentage by potty composition of northward in the plant food. To infer the sum up of nitrogen in ammonia water body of water, the NH4+ ion is reacted with an dissipation of NaOH, and the amount of unreacted NaOH bring by titration with HCl is employ to deduce the amount of NH4+ ion present by subtracting it from the initial amount of NaOH to find the amount th at reacted with it. From this, the percentage by vision of nitrogen present in the plant food tin mickle be found and subsequently compa reddened to the manufacturers specification.It is hypothesized that the percentage by mass of nitrogen present in the fertiliser go away be similar or close to that specified by the manufacturer (12.3%).Materials** 100 cm3 of 0.1 groyne dm-3 NaOH* 100 cm3 of 0.1 mol dm-3 HCl* 1.5 grams of fertiliser* 250 cm3 mountaintrical flaskful* 3 250 cm3 conelike flasks* 20 cm3 pipette* buret and retort stand* 50 cm3 mea for certain cylinder* Bunsen burner, tripod, gauze mat* Mortar and pounder* Electronic residual* White tile, bench mat* displace* Spatula* Red Litmus piece of music* methyl red indicator* guard duty Measures* Safety goggles must be cadaverous at all times. Sodium hydrated oxide rout out react with the proteins in the eye.* disclose a lab coat. Hydrochloric acid can ca utilisation severe skin irritation. If either is spil t on the skin, wash it off with body of water immediately.* Ammonia vapour irritates the skin, eyes, and respiratory system. manner1. Accurately weigh about 1.2 grams of fertilizer. tape the brand of the fertiliser and the nitrogen marrow as specified by the manufacturer.2. part the fertiliser in 250 cm3 of di salveed water in a volumetric flask. jibe the fertiliser first utilise a funnel and then app finish the water, allowing it to take with it the fertiliser remaining on the funnel, to the calibration line, stopper, and commotion the contents to dissolve the ammonium compounds in the fertilizer.3. Using a pipette, dispense 20 cm3 aliquots of the fertilizer stem into iii conical flasks.4. Thoroughly wash the pipette and dampen it with a small volume of quantity NaOH declaration. Place a 20 cm3 aliquot of NaOH ancestor in each of the flasks containing fertilizer declaration. Record the preoccupancy of the standard dissolving agent of NaOH.5. To one of the flasks, a dd 50 cm3 of distilled water. fag the variety for about 10 minutes. If necessary, add more water to maintain a incessant volume of resultant whilst boiling. experiment the vapour at the neck of the flask with a moist strip of red litmus story. If ammonia is present the paper will turn forbidding and high temperature should be continued until the point where litmus paper does non detect the battlefront of ammonia. Once this point has been reached, cool the flask under running water.6. Repeat measuring stick 5 with each of the other devil conical flasks.7. Rinse and fill a burette with standard HCl. Record the concentration of the acid and the initial burette reading.8. Add two to three drops of methyl red indicator to each conical flask containing the fertilizer mixture, and titrate. The decision point occurs when the ab initio yellow solution becomes orange tree. For each flask, phonograph record the burette reading once the end point has been reached.Data Collectio n carry over 1 Titration of the pointless NaOH (0.084 mol dm-3) against HCl using Methyl Red Indicator shoemakers last/EvaluationFertiliser is a rude(a) or synthetic chemical bone marrow or mixture that is utilise to enrich grime in order to press plant growth. It influences grass colourize, ability to domesticise from stress, and helps prevent weed invasions and diseases. Plants require more than a dozen different chemical elements but nitrogen, phosphorus, and potassium are the three major nutrients needed by lawns atomic number 7 is the nutrient required most as it promotes growth and keeps the grass green, although too overmuch nitrogen can encounter insidious effects on plants and crops, and on soil quality. In this investigation, the percentage by mass of nitrogen from the ammonium ion in the ideal fertiliser is being determined. The manufacturers claim of the amount of nitrogen present in this type of fertiliser is 12.3%.The ammonium that is present in fertilise rs is a washed-out acid, therefore it is hard to identify a sharp end point in direct titrations with the naked eye. Back titration is used instead. It is an analytical chemistry technique in which the unknown concentration of a reactant can be found by reacting it with an excess volume of other reactant of known concentration. The consequenceing mixture is then titrated back, taking into account the thou of the excess which was added. Before titration, the sodium hydroxide was reacted with ammonium in the fertiliser to seduce ammonia and waterNH4+(aq) + OH-(aq) NH3(g) + H2O(l)The basic solution needed for titration was reached through hotness the solution to remove the ammonium ions. By heating it, the rate of reaction between the ammonium ions and hydroxide ions increases, consequently producing water and ammonia. Since ammonia is an extremely volatile gas, boiling the solution will settlement the vaporization rate, which is the coveted outcome. The ammonium ions are als o the modification reagent thus once completely reacted, ammonia production ceases. This is indicated when the red litmus paper, which tests for the charge of a base, no keen-sighteder turns blue meaning the ammonia has completely evaporated and no ampleer present in the solution.By titrating the excess, unreacted hydroxide ions with standard hydrochloric acid, it allows us to await the amount of unreacted hydroxide ions since the molar ratio is equal, and from this the amount of reacted hydroxide ions with the fertiliser solution can be deduced. Subsequently, the amount of ammonium ions initially present in the 250 cm3 volumetric flask can be found and then the mass of nitrogen ions can be calculated. From this, the percentage by mass of nitrogen in the archetype of fertiliser can be found. It was found that the percentage by mass of 1.209 g of fertiliser was 13.87% (? 1.00%). This is very close to the percentage of nitrogen present in the fertiliser as specified by the manufa cturer 12.3%. This dissimilarity whitethorn be due to some(prenominal) errors and limitations encountered throughout the experiment.The percentage difference of 12.76% is great than the percentage uncertainty of 6.34% and as a consequence random errors unsocial cannot alone account for the difference. There must be systematic errors inherent to the investigation or the setup. Measurement errors could be the main computer address of uncertainty. One source of error could be that the exact mass of the fertiliser sample as measured on the electronic balance is not the same as in the volumetric flask, consequently poignant the final result. The loss due to the withdraw process into the flask which could be bring down by sufficiently rinsing the apparatus used to transfer, weigh and grind the fertiliser sample ? the funnel, weighing bottle, spatula and mortar and pestle ? so that all sample weighed is transferred into the volumetric flask. other possible error is that the menis cus of solutions measured was not sitting just on the calibration line in the volumetric flask when preparing the standard solution. This whitethorn affect the results as the expected volume of the standard solution would differ from the veritable volume measured. This can be get the better of by allowing more than one idiosyncratic to test whether or not the meniscus is positioned on the etched mark, making sure its at eye level, which will effectively limit this parallax error.The interpretation of the orange colour determined at the end point could also have been another(prenominal) error. Subjective judgment when determining the flavor of orange is another factor which whitethorn have affected the titer volume, and thus the final outcome. This problem was exacerbated by the fact that the methyl red indicator does not provide a sharp and slowly distinguishable end point, as the colour change from yellow to orange. This may be quash by using another indicator that allows for a clearer colour contrast.Another possible limitation which may have impacted the results is that some ammonia may still have been present in the conical flask. Although the red litmus paper may have served its purpose, this may still occur as a result of not boiling the solution long enough and thus some ammonia may not have evaporated. The result of this is that the ammonia in the solution will react with the hydrochloric acid, and therefore more hydrochloric acid will be required for the comparison point to be reached, affecting the titre volume. This can be easily tame by ensuring that the fertiliser solution containing water and sodium hydroxide is boiled for long enough so that all ammonia can evaporate, while simultaneously ensuring that the solution remains at a constant 90mL.The use of tap water may also have affected the results. It may not have been at a pH of 7 or may contain other contaminants such as salts which may ultimately interfere with the results. To over come this, the most effective way is to use deionised water.ConclusionIt was found that the percentage by mass of nitrogen from the ammonium ion in Bunnings Green Up brand of lawn fertilizer was 13.9% (? 1.00%). This was very close to the percentage of nitrogen in lawn fertiliser as specified by the manufacturer ? 12.3%.Bibliography1. Unknown Author, http//www.urbanext.uiuc.edu/lawntalk.htm2. interpersonal chemistry for the International Baccalaureate, 2005, IBID Press