Introduction

Potassium nitrate is a chemical compound with the formula KNO3. It belongs to a large group of compounds called "Saltpeter."  It is a white, odorless solid at room temperature and has a melting point of 334 degrees Celsius. Potassium nitrate forms crystalline solids at room temperature.

     It has a range of uses, from gun powder to fertilizers.  It has uses in the medical field, being shown to treat sensitive teeth, arthritis, high blood pressure, and chest pains.  It was used in the Middle Ages to preserve meat for the winter.  Potassium nitrate is used in rocket fuel and explosives to replace the need for oxygen in the reaction.  It helps make explosions stronger and is also used to make rocket fuel burn for a greater amount of time.

     Potassium nitrate is made by reacting ammonium nitrate (NH4NO3) with potassium hydroxide (KOH).  It can also form as natural crystals in dry caves and collects in bat guano.

    It has been used in gun powder and explosives for centuries.  It was created with a mixture of urine, ashes and straw.  The mixture fermented for months on end before it was exposed to the sun for excess liquid to evaporate.  The result was potassium nitrate.

Lewis Structures

Potassium nitrate is a polar molecule where electrons are both lost and gained.  One atom of oxygen gains an electron, while potassium and nitrogen lose an electron.

The nature of the bond between nitrogen and oxygen is strongly covalent, with an electronegativity of 0.5.  The nature of the bond between potassium and oxygen is both ionic and covalent, with an electronegativity of 1.7.

Potassium nitrate is a combination of two molecule structures: triangular planar (AX3) and bent (AX2E2).

Intermolecular Forces

Potassium nitrate is attracted to itself by two forces: London Dispersion and dipole-dipole.

Dipole-dipole is the attraction between two polar molecules.  Polar molecules have a slightly positive end and a slightly negative end.  When the molecules are oriented correctly, the opposite charges attract and create moderately strong bonds.

London Dispersion is the weakest intermolecular force.  It occurs in the brief moment when the electrons in a molecule are at a position to form a temporary dipole-dipole bond.  This happens when electrons are not distributed evenly around the nucleus.  This bond only happens for a fraction of a fraction of a second and is gone as soon as it happens, making it very weak.

3D Model

This is a 3D model of potassium nitrate that I made out of puff balls and toothpicks.  The orange ball represents nitrogen, the blue represents oxygen, the white is potassium, and the purple, sparkly puffs are unshared electron pairs.

There is a double bond between nitrogen and the oxygen farthest to the left.

The nitrogen and oxygen structure is an AX3, triangular planar, molecule, so there is a 120 degree angle between each nitrogen-oxygen bond.

The nitrogen-oxygen-potassium structure is bent (AX2E2), with an angle of 109.5 degrees.

3D Model Attempt 1

This is an attempt at a model of potassium nitrate made out of fruit.  Nitrogen is the mango, potassium is the clementine, and the grapes are oxygen.

Sadly, I got hungry (with a craving for fruit), and the model was no more. :/

Conclusion

   The most fascinating thing about potassium nitrate is its wide variety of uses.  It is used in gunpowder and fireworks, toothpaste, preservatives, fire extinguishers and many more!  Some of its uses were also discovered more than seven hundred years ago.  With limited technology, people could make potassium nitrate by using things they found in nature; they didn't have labs like the ones we have today.

    Some hazards of potassium nitrate are that it is an oxidant, causes irritation to the eyes and skin, and can be harmful if swallowed.