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General |
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| Name | Potassium nitrate |
| Chemical formula | K NO3 |
| Appearance | White or dirty gray solid |
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Physical |
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| Formula weight | 101.1 amu |
| Melting point | 607 K (334 °C) |
| Boiling point | decomposes at 673 K (400 °C) |
| Density | 2.1 ×103 kg/ m3 |
| Crystal structure | Aragonite |
| Solubility | 38 gFor other meanings of gram see gram (disambiguation). The gram (also spelt gramme is a unit of measurement of mass, and is defined in the SI system of units as one thousandth of a kilogram. See 1 E -3 kg for comparisons with other masses. The symbol for g in 100g water |
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Thermochemistry |
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| ΔfH0gasThe standard enthalpy of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of that substance from its component elements, at their standard states (the most stable form of the element or compound at 25 degrees Cels | ? kJThe joule (symbol J also called newton metre or coulomb volt is the SI unit of energy and work. The unit is pronounced to rhyme with "tool", and is named in honour of the physicist James Prescott Joule (1818-1889). 1 joule 1 N · 1 m 1 newton · 1 metre 1 k/ molThe mole (symbol: mol) is one of the seven SI base units and is commonly used in chemistry. It measures the amount of substance of a system and is defined as the amount of substance that contains as many elementary entities as there are atoms in exactly 0 |
| ΔfH0liquidThe standard enthalpy of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of that substance from its component elements, at their standard states (the most stable form of the element or compound at 25 degrees Cels | -483 kJ/mol |
| ΔfH0solidThe standard enthalpy of formation of a compound is the change of enthalpy that accompanies the formation of 1 mole of that substance from its component elements, at their standard states (the most stable form of the element or compound at 25 degrees Cels | -495 kJ/mol |
| S0gas, 1 bar | ? J/mol·K |
| S0liquid, 1 bar | ? J/mol·K |
| S0solid | ? J/mol·K |
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Safety | |
| Ingestion | May cause GI irritation, nausea, vomiting, diarrhea. |
| Inhalation | Irritation, long term exposure may be fatal. |
| Skin | Low hazard. |
| Eyes | Low hazard. |
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SI units were used where possible. Unless otherwise stated, standard conditions were used. | |
The chemical compound potassium nitrate is a naturally occurring mineral source of nitrogen. It is a nitrate with chemical formula K N O3.
Its common names include saltpetre (from Medieval Latin sal petrae: "stone salt" or possibly "salt of Petra"), American English saltpeter, Chilean saltpetre, and nitre. The name saltpeter is also applied to sodium nitrate.
It is the oxidising ( oxygen-supplying) component of gunpowder. Prior to the large-scale industrial fixation of nitrogen (the Haber process), a major source of Potassium nitrate was the deposits crystallising from cave walls or the drainings of decomposing organic material. Dung-heaps were a particularly common source: ammonia from the decomposition of urea and other nitrogenous materials would undergo bacterial oxidation to produce nitrate.
One of the most useful applications of potassium nitrate is in the production of nitric acid, by adding concentrated sulfuric acid to an aqueous solution of potassium nitrate, yielding nitric acid and potassium sulfate which are separated through fractional distillation.
Potassium nitrate is also used as a fertilizer, as a model rocket propellant, and for certain pyrotechnic combinations, like when potassium nitrate is mixed with fine sugar and ignited, they generate 600 times their own volume in smoke. In the process of food preservation, potassium nitrate is a common ingredient of salted meat.
In England, the privilege of manufacturing explosives had been in the hands of the family of John Evelyn, the celebrated diarist, as a crown monopoly since before 1588.