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Calcium chloride

physical science Maturity 7-9 Next article →

Calcium chloride is an inorganic compound with the chemical formula CaCl2. It appears as a white crystalline solid at room temperature. This salt is highly soluble, meaning it dissolves very easily in water. When it dissolves, it undergoes an exothermic process. This means the reaction releases energy in the form of heat. Because of these unique chemical properties, calcium chloride is used in many different industries. It can be found in everything from road maintenance to the food we eat.

One of the most important ways calcium chloride works is through freezing-point depression. This process lowers the temperature at which water turns into ice. Because of this, calcium chloride is a very effective de-icing agent. It works much better than sodium chloride, which is common table salt, in very cold temperatures. For road use, it is often applied as small white spheres called prills. These solutions can prevent freezing at temperatures as low as -52°C.

Cacl2 storage for winter road in japan
Cacl2 storage for winter road in japan

This makes it useful for liquid ballast in agricultural tires to aid traction in cold climates.

Another major use for this compound involves its hygroscopic nature. A hygroscopic substance is one that attracts and holds water molecules from the surrounding environment. Calcium chloride is also deliquescent, which means it can absorb so much water that it eventually dissolves into a liquid. This property is used for dust control on dirt roads. When sprayed on a road, it creates a tacky, wet layer on the surface. This layer holds fine dust particles in place. This prevents the road from breaking down and can reduce the need for grading by 50%. It can also reduce the need for fill-in materials by as much as 80%.

Calcium chloride on a dirt road
Calcium chloride on a dirt road

In the food industry, calcium chloride acts as a firming agent. It is frequently used in canned vegetables like tomatoes and cucumber pickles. It also helps firm soybean curds into tofu and creates caviar substitutes from fruit juices. The salt works through several biological mechanisms. It can form coordination complexes with pectin, which is a polysaccharide in plant cell walls. It also helps stabilize cell membranes and regulates turgor pressure. Turgor pressure is the pressure of the cell contents against the cell wall. This helps maintain the texture of items like sliced apples, strawberries, and peaches.

History shows that humans have known about calcium chloride for a long time. It was apparently discovered in the 15th century. However, it was not studied properly until the 18th century. In the past, it was called "fixed sal ammoniac." This was because it was created during the distillation of ammonium chloride with lime. During the 18th and 19th centuries, it was commonly called "muriate of lime." These names reflect how scientists understood its production and its nonvolatile nature.

Calcium chloride also has many specialized uses in science and industry. In medicine, it can be used as an intravenous therapy to prevent hypocalcemia, a condition where calcium levels are too low. In the brewing industry, it can correct mineral deficiencies in water to affect flavor and yeast function. It is even used in the FFC Cambridge electrolysis process to produce titanium. In this process, it acts as a flux and an electrolyte to help exchange calcium and oxygen ions.

Flame Test Ca
Flame Test Ca

It can also be used in the Davy process to produce sodium metal by lowering the melting point of molten CaCl2.

While useful, the substance must be handled with care. Because it is highly soluble and exothermic, ingesting undissolved crystals can cause burns in the mouth, throat, or stomach. It also has a very salty and bitter taste. The bitterness comes from calcium ions interacting with the TAS2R family of bitter taste receptors in humans. In high concentrations, it can cause irritation to the skin by removing moisture. Despite these risks, the U.S. Food and Drug Administration recognizes it as generally safe for food use. It is used in small amounts as an additive in many common products.

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File:Cacl2 storage for winter road in japan.jpg
Cacl2 storage for winter road in japan.jpg
File:Calcium chloride on a dirt road.jpg
Calcium chloride on a dirt road.jpg
File:Flame Test Ca.jpg
Flame Test Ca.jpg
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