Synthesis of Potassium Nitrate
A. Objectives Study the synthesis of potassium nitrate salt from the reaction between sodium nitrate and potassium chloride; Study the separation process this salt from sodium chloride by product based on the differences in solubility. B. Theoretical Bases Potassium nitrate is a chemical compound that is a natural source of nitrogen. These compounds are classified as nitrate compound with chemical formula KNO3. The name generally includes saltpeter (saltpeter). Potassium nitrate is a component of black powder oxidized (supplied energy). Before large-scale nitrogen fixation industry (process Harker). The main source of potassium nitrate was crystallized deposit from the walls of caves or decaying organic rot material. Piles of dirt are also the main source of general, decomposition of ammonia from urea and other nitrogen substances going through bacterial oxidation to produce nitrates. Potassium nitrate can also be made of potassium chloride contained in sulvit minerals with sodium nitrate. If a saturated solution of each reaction was mixed, the less soluble NaCl would precipitated. The reaction: KCl (aq) + NaNO3 (aq) NaCl (s) + KNO3 (aq) If the solution is cooled, then the solution will precipitate. These deposits can be separated and then purified by recrystallization. Potassium nitrate crystallizes in rhombic prism shape, but if the solution was evaporated slowly on the watch glass will crystallize in the form rombohedial isomof. In this experiment used crystallization method, is a method of separation by means of the formation of crystals so the solution could be disparate. A gas or liquid substance can be cooled or condense and form crystals because crystallization process. The crystals also be formed from a solution that will be saturated with a particular solvent. The more the crystals, the better, because the less likely contaminated by feces. Most of the nitrate salt is hygroscopic and readily soluble in water. Some of the nitrate salt is obtained in the form of anhydrous and do not decompose on heating which is quite high. While the molecular orbital theory explained that nitrogen bond forming three hybrid orbitals using the SP and P orbital of nitrogen and three oxygen atoms combine to form molecular orbitals are occupied by two electrons. Nitrate salts of almost all metals are known. Inside, the nitrate salts are often found in Chile, especially in the form of sodium nitrate. Maybe because it's a common name sodium nitrate is belching chilli, while the term used to burp common name potassium nitrate salt. Most of the nitrate salts are hygroscopic and readily soluble in water. Some nitrate salts can be obtained in the form of anhydrous and do not decompose on heating is high enough.
Nitrate is one type of chemical compounds that are often found in nature, such as in plants and water. This compound is found in three forms, namely nitrate ions (ionNO)3, potassium nitrate (KNO3), and nitrate nitrogen (NO3-N). The third form of nitrate compounds cause the same effect on livestock although at different concentrations (Stoltenow dan Lardy 1998; Cassel dan Barao 2000). Actually nitrate is not toxic to animals. However, the consumption of excessive amounts and high concentrations can cause poisoning, because with the help of rumen bacteria, nitrates are reduced to nitrites were 10 times more toxic than nitrate. Furthermore, nitrite ions are absorbed into the blood, and when it comes in contact with erythrocytes, nitrite oxidizes Fe + 2 in hemoglobin (Hb) into Fe 3+ to form methaemoglobin (MetHb). The content of 30-40% MetHb in the blood can cause clinical symptoms, and when containing up to 80-90% will cause death in cattle (Clarke and Clarke 1976; Osweiler et al. 1976). According to Robson (2007), some animals can tolerate up to 50% MetHb content without causing symptoms. However, if the content exceeds 80% MetHb will cause death in animals (Yuningsih, 2007). One of the most useful applications of potassium nitrate is in the production of nitric acid, by adding sulphate acid aqueous potassium nitrate, yielding nitric acid and potassium sulphate which are separated through fractional distillation. concentrated on Potassium nitrate is also used as a fertilizer, as a model rocket propellant, and in some firecrackers such as smoke bombs, in which a mixture with sugar produces soot from the smoke 600 times its own volume it occupies. In the process of food preservation, potassium nitrate is a common composition of meat are marinated. Potassium Nitrate is also a major component in busting butts. It has also been used in the manufacture of ice cream. The false famous conception is that potassium nitrate added to food in the usual custom done man. In fact potassium nitrate does not have such an effect in humans. Now, the use of potassium nitrate in toothpaste for sensitive teeth has increased dramatically, although in fact has not revealed to help with the actual tooth hypersensitivity. Influence of temperature rise on the solubility of a substance different from one another. Differences can be used to separate mixtures of two or more substances by means of recrystallization storey, for example memisahakan KNO 3 with NaCl. From the experiment looks kelarytan KNO3 greatly affected by temperature increase while NaCl is not terpengaruholeh temperature. If the mixture is put in hot water then KNO3lebih solubility greater than that of sodium chloride natriumklorida more crystallized at high temperature in hot conditions. If the liquid is cooled KNO3 settles. The precipitate is separated then purified by means of recrystallization. The common name for KNO3 was belching, whereas NaNO3 Chile saltpeter. Potassium nitrate crystallizes in rhombic crystal form, but if the solution in uapkan slowly on the watch glass will crystallize in the rhombohedral form, isomorphous with sodium nitrate and calcite.
C. Method We used the equipment: 1 set of spiritus burner (gauze, foot three, stove methylated); 2 of beakerglass 100 ml; 1 200 ml beakerglass; Basin; Mixer; drop pipette 3 pieces; filter paper; funnel The material we used:
4.2533 grams NaNO3 for sys Merck brand;
3.7494 grams KCl sys from Merck brand;
Ice;
Distillated water.
Steps of Work: 1. Synthesis of KNO3 salt Potassium cholire crystall (KCl)
Sodium Nitrate (NaNO3)
- weight 3,75 grams
- weight 4,25 grams
- dilute with 7,5 mL aquadest in 100 mL beaker glass
- dilute in 7,5 mL hot water in 100 mL beaker glass
- stir
- stir
Solution A
Solution B
- mix the solution then stir - Evaporate the solution - Cooling it down in ice bath - Filter the crystall
Filtrate
b. KNO3 Purification
Crystall KNO3 (impure) - Recryst with aquadest - Dry the crystall Pure Crystall KNO3 Weight % Rendemen = 67,75 %
Crystall KNO3 (impure)
Observation Data
Colour and structure of KCl Colour and structure of KNO3 Colour and structure of NaNO3 Reaction occurs in the experiment:
: solid powder, white : white, needle shaped crystal : white, solid powder
KCl(s) + H2O(l) KCl(aq) NaNO3(s) + H2O(l) NaNO3(aq) KCl(aq) + NaNO3(aq) NaCl(aq) + KNO3(aq) KNO3(aq) KNO3(s)
Weight of KNO3(s) : 3.4214 grams Colour of structure crystal of KNO3(s): white, crystal ruse The percentage of KNO3 yield: Mol KCl
:
Mol NaNO3
:
3.7494 74.5 4.2533 85
= 0.0503mol = 0.0500mol
KCl(aq) + NaNO3(aq) NaCl(aq) + KNO3(aq) Mass of KNO3
=
n * MrKNO3 = 0.05 * 101 = 5.05 gram
% KNO3
= 𝑇ℎ𝑒𝑜𝑟𝑒𝑡𝑖𝑐𝑎𝑙 𝑚𝑎𝑠𝑠 𝑥100%
𝑊𝑒𝑖𝑔ℎ𝑡 𝑐𝑟𝑦𝑠𝑡𝑎𝑙𝑙
3.1457 5.058
= 100% = 62.2 %
D. Discussion Potassium Nitrate is a compound of potassium nitrate salts with molecular formula KNO3. Potassium nitrate salts can be prepared by reacting potassium chloride, KCl found in mineral silvi, with sodium nitrate NaNO3. If a saturated solution of each of these reactions are mixed with each other, it will form sodium chloride, NaCl and KNO3 as a solvent solution of NaCl in water is very small, then the salt will undergo precipitation, and through filtering KNO3 solution can be separated from NaCl. By cooling the filtrate slowly, then KNO3 (aq) will undergo crystallization process, and to make KNO3 crystallization. One of the most useful applications of potassium nitrate is in the production of nitric acid, by adding concentrated sulphuric acid in an aqueous solution of potassium nitrate, yielding nitric acid and potassium sulphate which are separated through fractional distillation. Now, the use of potassium nitrate in toothpaste for sensitive teeth has increased dramatically, although in fact has not revealed to help with the actual tooth hypersensitivity. The chemical compound potassium nitrate is a natural source of mineral nitrogen. These compounds are classified as nitrate compound with chemical formula KNO3. The name generally includes saltpeter (saltpetre / saltpeter). The name saltpeter is also applied to sodium nitrate. Potassium nitrate is also a component of black powder oxidized (supplied oxygen). Before fixation of large-scale industrial nitrogen (Haber process), the main source of Potassium nitrate is a deposit which crystallized from cave walls or drain decaying organic material. Piles of dirt are also the main source of general, decomposition of ammonia from urea and other nitrogen substances going through bacterial oxidation to produce nitrates. Potassium nitrate can be obtained by reacting potassium chloride with sodium nitrate, as is done in this experiment. This experiment was started by reacting potassium chloride (KCl) with sodium nitrate (NaNO3) which has been diluted with hot water, then evaporated to a volume of 10 ml. The reaction: KCl(s) + H2O(aq) K+(aq) + ClNaNO3(s) + H2O(aq) Na+(aq) + NO3NaNO3(aq) + KCl(aq) KNO3(s) + NaCl (KNO3 : needles shaped white crystals)
When heating / evaporation was done, the desired crystal was formed we perform cooling by placing the beaker containing the solution mixture in a bowl filled with ice cubes. After cooling the crystals of potassium nitrate (KNO3) were separated from the liquid by filtration, and recrystallization or purification crystals made with distilled water so that the liquid crystal was free of chloride and other impurities, so that a crystal of potassium nitrate to be obtained from the changes into rhombic hedral rhombic shape. Crystals produced is white and shaped like needles.
Figure 1. Relationship between temperature and solubility of KNO3, NaNO3, KCl and NaCl
Crystals are formed for a while still wet, so we need to dry themwe use the filter paper to obtain white crystals were dried. After weighing using analytical balance weight gained is equal to 3.1457 grams. From the observed data, the results obtained yield amounted to: 𝑚𝑎𝑠𝑠𝑎 (𝑔𝑟𝑎𝑚) 3.7494 = = 0.0503 𝑚𝑜𝑙 𝑀𝑟 𝐾𝐶𝑙 74.5 𝑚𝑎𝑠𝑠𝑎 (𝑔𝑟𝑎𝑚) 4.2533 𝑛 𝑁𝑎𝑁𝑂3 = = = 0.0500 𝑚𝑜𝑙 𝑀𝑟 𝑁𝑎𝑁𝑂3 85 𝑛 𝐾𝐶𝑙 =
KCl
+ NaNO3
M
0.0503
0.0500
R
0.0500
0.0500
S
0.0003
KNO3
+ NaCl
0.0500
0.0500
0.0500
0.0500
-
𝑚 𝐾𝑁𝑂3 = 0.0500 𝑥 101 = 5.05 𝑔𝑟𝑎𝑚 The percentage of KNO3 yield: 3.4214 5.05
= 100% = 67.75 %
E. Conclusion From the experiments we can conclude that potassium nitrate crystals can be produced by reacting solid KCl and solid NaNO3. In the reaction between KCl with NaNO3 other than potassium nitrate produced crystal also produced NaCl which can later be separated by cooling with ice. Thus obtained solid KNO3 crystals are white and shaped like a needle. Potassium nitrate crystals formed 3.4214 grams with a yield of 67.75% in this experiment. F. Suggestion The result will be better if the temperature when KNO3 purification is lower. The filtrate of NaCl can be repeated to cooled to get more potassium nitrate crystals. G. References Arsyad. 2001. Kamus Kimia. Jakarta: PT Gramedia Pustaka utama. Svehla. 1990. Analisis Anorganik Kualitatif Makro dan Semimikro. Jakarta: PT. Kalman Media Pustaka Vogel. 1990. Organic Analysis Qualitative Macro and Micro. Oxford: New york Azis, T. 2007. Penuntun Praktikum Kimia Anorganik. Kendari: Jurusan Kimia Universitas Haluoleo.
