Fertilizers: Potassium and Compounds

Creating a liquid fertilizer Experiment Chemistry 1065 10/09/2012 Introduction The aim of this experiment was to create a liquid fertilizer containing Nitrogen, potassium and phosphorus; each element had to have 8% mass percentage. We were also required to add an additional element, magnesium and it mass percentage had to be 1. 5%. At the end of the experiment, the pH of our aqueous solution had to be between 6. 0 and 7. 0.As a group we predicted that we could not successfully create the liquid fertilizer with the compounds we were provided with, because some of the compounds would create a precipitate if mixed. As a result we decided that it would be take further experimentation of trying different combination of these compounds on small scale to help us successfully create the required fertilizer. This experiment is important because it is necessary to make a plant fertilizer that is environment friendly and that provides various plants with the nutrients they need to grow.This exp eriment was interesting because gave us the chance to see get in the perspective of the scientists who constantly keep working towards making the best possible fertilizers for plants. Recent attempts by scientists of making the ‘ideal fertilizer have failed because either the fertilizer is not environment friendly or it increases the birth-rate of agricultural pests. In this lab, we created several compound combinations to try and match the compounds in the required fertilizer.Some of our combinations worked, but some failed. We made adjustments to the original information provided to us in order to meet the standards of the required liquid fertilizer, and as a group we tried our best to indicate such adjustments throughout our lab reports so that the reader can be more informed about the experiment we did. . Experimental Because our prediction was that some of the provided compounds would not for an aqueous solution, we decided to try out some combinations on small scale to s ee how they reacted.The compounds we needed for these combinations were: Potassium carbonate, trisodium phosphate, potassium nitrate, ammonium carbonate, sodium phosphate, and sodium nitrate. We also needed some water to dissolve these compounds in. In order to perform a solubility test on the provided compounds we obtained a well plate, a spatula to add the solid compounds into the well plate, a beaker full of distilled water, a pipette to add water into the well plates containing two different compounds, and a stirring rod to stir the mixture.First using a spatula we took a small amount of K2CO3 and put in one of the wells on the well plate. Then we took a small sample of Na3PO4 and put it in the same well. Using a pipette we took 3ml of distilled water from the beaker and added it into the well containing K2CO3 and Na3PO4. The using a stirring rod, we continuously stirred the solution for 1 minute and we observed. Then we took small samples of K2Co3 and NH4Co3 and put them in a s econd well on the well plate. Then we added 3ml of water using a pipette. Using a stirring rod, we mixed the solution continuously for about a minute.Next we took small samples of NaNO3 and NaPO3 and put them in a third well on the well plate. We added some water using a pipette and stirred up the solution. Then we took samples of NaPO3 and KNO3 and put them in a fourth well in the well plate. We added 3 ml of water, stirred the solution and observed. Next we took samples of Na2PO3, K2CO3 and NaNO3 and put them in a fifth well. We added 3ml of water, constantly stirred the solution and observed. We then took samples of Na2PO3, K2CO3 and NaNO3 and put them in a sixth well plate.Then we added 3ml of water and constantly stirred the solution for a minute and observed. Through eliminating solutions that formed a precipitate we chose the solution containing, Na2PO3, K2CO3 and NaNO3 as the solution that could potentially be our liquid fertilizer because it contained nitrogen, phosphorus a nd potassium ions. Because we needed nitrogen, phosphorus and potassium to each have an 8% mass percentage in relation to the total solution, we calculated how much of each compound we needed so that the three required elements could have 8% mass percentage each in 10g of H2O.We calculate the amount of each compound needed by first figuring it in moles and then we converted it to grams. We replaced Na2PO3 with Na3PO4 because Na2PO3 was unavailable. After calculating how much of each compound we needed to make our fertilizer, we decided that we needed a beaker, a scale, weighing paper, pH probe, graduated cylinder, stirring rod, Magnesium and H2SO4 to neutralize our solution at the end. We started by weighing out 4. 23481g of Na3PO4, 0. 707g of K2CO3, and 5. 8221g NaNO3. Then we poured the weighed compounds into a beaker.We then measured 10ml of distilled water using a graduated cylinder. We then poured the 10ml water into the beaker containing our three compounds. Using a stirring r od we stirred the mixture for about three minutes. The compounds did not dissolve in water because the ratio of the compounds to the water could not allow the compounds to completely dissolve in the water. With instructions from our T. A we decided to divide the amount of all the compounds by 10. The new amounts of the compounds were: 0. 423481g of Na3PO4, 0. 0707g of K2CO3, and 0. 58221g NaNO3. We then weighed out these new amounts of compounds.We poured them into a new beaker and added 10 ml water. Using a stirring rod, we continuously stirred the solution until the compounds were completely dissolved. Next we got a pH probe to measure the pH of our solution. The pH of our solution needed to be between 6. 0 and 7. 0. We connected the loggerpro software to a laptop and we the pH collected was 12. 43. Since our fertilizer solution was a base we decided to neutralize it using an acid. The acid we chose to use was H2SO4. Using a pipette we added drops of H2SO4 to our fertilizer soluti on as we monitored the pH of our solution.It took 2. 4ml of H2SO4 to bring the pH of our liquid fertilizer to 6. 75. To make our liquid fertilizer complete we were required to add an additional element, magnesium such that it had a 5% mass percentage. We chose to use the compound magnesium nitrate because it contains a magnesium ion. We calculated that in order for magnesium to have a 5% mass percentage in the solution we needed 3. 05g of Mg (NO3)2. But because we had divided the other compounds in the solution by ten earlier, we had to divide the amount of Mg (NO3)2 paste to keep the same ratio.So after dividing the amount of magnesium needed by 10 we resulted with 0. 305g of Mg. We then weighed 0. 305g of Mg (NO3)2 on a scale and the poured it into the beaker containing our aqueous solution. Using a stirring rod we stirred up the solution until the Mg (NO3)2 was completely dissolved. We then finished the experiment by measuring the final pH of our solution which was 6. 7. Results Data 1 Compounds added to 10ml of water| Observations| KNO3 & NaPO3| When we mixed these two compounds in water, they formed a cloudy solution which turned clear after a while.There was some compound left at the bottom of the beaker and this was due to experimental error. | K2CO3 & NH4CO3| When we mixed these two compounds, they formed a cloudy mixture. One of the compounds looked suspended which meant it did not dissolve. | NaNO3 & K2CO3| When we mixed these two compounds, they both dissolved in the water although there was some compound particles left at the bottom of the beaker which was due to experimental error. | NaNO3 & NaPO3| When we mixed these two compounds, they formed a precipitate. NaPO3 & KNO3| When we mixed these two compounds, they did not dissolve in water, they formed a precipitate| Na2PO3, K2CO3 & NaNO3| When we mixed these three compounds in water, the completely dissolved| Data 2 Substance added to 10 ml of water| Observation| 4. 234g Na3PO4, 0. 707g K2CO3, and 5. 8221g NaNO3| Did not dissolve in water. The amount ratio of compounds was too big to dissolve. | 0. 423481g Na3PO4, 0. 0707g K2CO3, and 0. 58221g NaNO3| Completely dissolved in water and the pH of the resulting solution was 12. 3| 1 ml H2SO4| pH of solution dropped to 11. 14| 2ml H2SO4| pH of solution dropped to 7. 45| 2. 4ml H2SO4| pH dropped to 6. 7| 0. 03052 g Mg(NO3)2| Completely dissolved in water and the pH stayed at 6. 7| Calculations Amount of compounds needed. Note: We divided the final amount of the compound needed by 10 so that it would dissolve in water. What we need: 10g ? 8%= 0. 8 g N, 0. 8g P, 0. 8g K Element| Calculations| Amount of compound so that element has 8% mass percentage| Amount of compound so that element has 0. 8% mass percentage| Nitrogen| 0. g N3- ? (1 mol N2 / 14. 01g/mol N2)= 0. 057mol N20. 57mol N3- ? (101. 96 g/mol NaNO3) | 5. 8221g NaNo3| 0. 5221g NaNo3 | Potassium| 0. 4g K2+ ? (1 mol K2+ / 78. 2g/mol K)= 0. 005115 mol K2+0. 005115 mol K2+ ? (138 . 21 g/mol K2CO3) | . 707 g K2CO3 | 0. 0707g K2CO3| Phosphorus| 0. 8g P3- ? (1 mol P3-/30. 97g/mol P)= 0. 02583mol P3-0. 02583mol P3- ? (163. 94g/mol Na3PO4)| 4. 23481g Na3Po4| 0. 0423481g Na3Po4| Note: We used 0. 4g of Potassium because there are 2 potassium ions in K2CO3