More than 1,000 years ago, someone made the coincidental discovery that a mixture of sulfur, charcoal, and potassium nitrate burned with startling speed and flash. The mixture, which eventually came to be known as gunpowder, was a Chinese mainstay for centuries, used in ceremonies to scare off evil spirits and even in military rockets. It wasn't until the 1800s that chemists began to use then-recently synthesized compounds that, in the right mixtures, burned in reds, greens, even blues and purples, and that the colors we traditionally ascribe to fireworks began to show up in night skies. Today, fireworks makers rely on compounds such as barium nitrate, strontium carbonate or nitrate, sodium oxalate, and copper carbonate.
The chief use of Nitrate is in fertilizers. Anyone who has grown a garden, maintained a lawn, or kept houseplants knows that it is necessary to apply a fertilizer to the soil to keep cultivated plants healthy. As they grow, plants extract nutrients they need from the soil. Unless these nutrients are replenished, plants will eventually cease to grow. Ammonium is made up of nitrogen and hydrogen, three particles of hydrogen for each particle of nitrogen. (NH3-). Shortly after the ammonium reaches the soil, it binds to soil or organic matter. Through time, it is converted to nitrate by soil bacteria. The warmer the soil, the faster the conversion. It is the nitrate form of N that is most mobile in the soil and most likely to leach into groundwater. During the conversion to nitrate, the nitrogen element loses three hydrogen atoms and adds two oxygen atoms, from the air in the soil. Unfortunately, Nitrate can be poisonous. Nitrate in itself is not toxic to animals, but at elevated levels it causes a disease called nitrate poisoning. Nitrates are normally found in forages are converted by the digestion process to nitrite, and in turn the nitrite is converted to ammonia. The ammonia is then converted to protein by bacteria in the rumen. If cattle rapidly ingest large quantities of plants that contain high levels of nitrate, nitrite will accumulate in the rumen. Nitrite is ten times (10 X) as toxic to cattle as nitrate.
Nitrites are completely different from Nitrates. Nitrites used in heart remedies and making dyes in cured meats, such as bacon, to prevent botulism, and to give meat a pink color. Amyl nitrite was discovered in 1857 and was being used ten years later as a treatment for angina (a heart condition) due to its ability to open up the vessels delivering blood to the heart. Amyl nitrite is now hardly ever prescribed as a medicine (if at all) as it has been superseded by longer acting and more effective medicines. Butyl nitrite is very similar to amyl nitrite but produces slightly less potent effects. When used in meats, nitrate itself is harmless, it is readily converted to nitrite. When nitrite combines with compounds called secondary amines, it forms nitrosamines. This is an extremely powerful cancer-causing chemical. The chemical reaction occurs most readily at the high temperatures of frying. Nitrite has long been suspected as being a cause of stomach cancer.
Zinc sulfate is used in surgery as an antiseptic, in calico printing, and in making drying oils for varnishes.
