Natural chalk is a common form of calcium carbonate. Unlike other, chemically similar minerals, chalk deposits are laid down by living organisms known as coccolithophores. These microscopic animals thrive in the warm, shallow seas that proliferated in the Cretaceous Period, which derives its name from the Latin word for chalk.Know More
Natural chalk has been used in its raw form by artists for as long as humans have been etching cave walls. Sometimes impurities are found in the chalk bed, which lend various colors to the chalk. Commercial chalk is usually derived from natural chalk, but with various additives to enrich the color and give it greater strength.
Commercial chalk, of the kind most often used in classrooms, is made from ground chalk powder that has been hydrated and mixed with clay for a firmer consistency. Dyes can be added to give the chalk a desired color. Black chalk, for example, usually contains carbon. Red chalk is often made with ferric oxide, which is a mineral form of iron and oxygen. Some "dustless" varieties of chalk are sold as sticks that have been dipped in a vat of artificial shellac that binds and seals the stick's surface and keeps the chalk from shedding.Learn more about Chemistry
Chalk is calcium carbonate and has the same chemical composition as limestone, marble, ground calcium carbonate and precipitated calcium carbonate. Chalk, like the other types of calcium carbonate, is in the form of calcite, which is a crystal.Full Answer >
The most common chemical formulas for chalk are CaCO3 (calcium carbonate) and CaO (calcium oxide). Chalk is a soft, porous sedimentary rock that is a form of limestone and is mainly composed of calcite (calcium carbonate).Full Answer >
The primary ingredient of levothyroxine is synthetic T-4, which is identical to the hormone produced in the thyroid gland. Levothyroxine also contains inactive ingredients common in prescription medications. These inactive ingredients don't alter its effectiveness but add color, enable a longer shelf life and increase efficiency in manufacturing the medication.Full Answer >
Plastic is derived from organic substances including crude oil, salt, cellulose, coal and natural gas. Crude oil, one of the main ingredients of plastic, is a complex compound that must be broken down into fractions (mixtures of compounds made up of carbon and hydrogen) in order to be used effectively.Full Answer >