Chalk
Chalk dust is primarily made of calcium carbonate, a type of limestone composed mainly of calcite. It also contains small amounts of other minerals, such as quartz, clay, and mica. When chalk is used on a blackboard, the friction creates the dust that we see.
Tailor's Chalk is made from magnesium silicate or Mg3Si4O10(OH)2. Blackboard/ Chalkboard Chalk is made from calcium sulfate or CaSO4. Both were previously made from chalk a form of limestone that is a soft, white, porous sedimentary rock composed of calcium carbonate or CaCO3. Other Names for Tailor's Chalk: Sewing Chalk, Magnesium Silicate, Soapstone, Talc, Slate Other Names for Chalkboard/Blackboard Chalk: Calcium Sulfate, Gypsum, Gypsum Plaster, Plaster of Paris, Drierite, Alabaster, Anhydrite, Desert Rose * Tailor's Chalk is used to temporarily mark clothing for alterations. * Chalkboard/Blackboard Chalk is used for writing and/or drawing on a chalkboard, blackboard, slate, or enamel board. * Tailor's Chalk and Blackboard/Chalkboard Chalk are interchangeable though the method of cleanup varies if the before mentioned chalk is used for it's intended purpose or another usage. * Chalkboard/Blackboard Chalk made from calcium sulfate is dust free. * Chalk Sticks are made from calcium sulfate (calcium & sulphur molecules chemically bound to water) aka gypsum in its dihydrate form (chemical compound containing 2 molecules of water around each CaSO4 group aka calcium sulfate hemihydrate * Chalk Sticks are made through calcination. Calcination is a treatment process of removing water from a substance or compound in this case calcium sulfate by heating the calcium sulfate to a high temperature that is also below melting or fusing point causing a loss of 50% to 75% of the calcium sulfate's original moisture producing a powder. When water is then added to the powder it rehydrates and quickly hardens. * Calcium Sulfate predominately comes from Gypsum or Anhydrite though it also occurs as a byproduct of several different chemical processes * Gypsum or Anhydrite occurs in many locations worldwide as evaporites (a natural salt or mineral sediment deposit left after the evaporation of a body of water) * Pastels are made from calcium sulfate mixed with clay, oils, & pigment * Soapstone is a metamorphic rock made mostly of Talc aka Magnesium Silicate * Soapstone aka slate is what blackboards were first made from though most modern chalkboards are made with steel treated with an enamel * Chalkboards can be made any color; Blackboards refer to the original blackboards made from soapstone aka slate * Modern chalkboards are made with tiling grout; one of the main ingredients in tiling grout is Magnesium Silicate same as original Blackboards and Tailor's Chalk * In early American schools children used a slate aka soapstone pencil to write on personal slate aka soapstone boards. These slate aka soapstone pencils were a cylinder of the rock inside cedar * Slate pencils were replaced by soft chalk aka calcium carbonate (CaCO3) later replaced by calcium sulfate aka gypsum (CaSO4·2H2O)
Chalk is made out of Calcium Sulphate and it dissolves in weak acids which means it is a weak chemical to acids. So the vinegar wich is a typr of an acid dissolves the chalk with cool foams foaming in the jug or a cup. because of the acid in the vinegar EDIT(Dr.J.): Actually, chalk is mostly calcium carbonate, not calcium sulphate. The carbonate reacts with acetic acid (vinegar) to create CO2 and H2O as follows: CaCO3 + 2CH3COOH ==> Ca(CH3COO)2 + 2H2CO3 ==> 2CO2 + 2H2O
Chalk, primarily composed of calcium carbonate, does not dissolve in alcohol. Instead, it is insoluble in most organic solvents, including alcohol. While some components of chalk may react with acids, the overall structure remains intact in alcoholic solutions. Thus, chalk will not dissolve in alcohol.
most likely,
Most of the chalk available in the US is certainly manufactured to be non-toxic and in some cases even hypo-allergenic. The liability is too great for the producer not to insure that it is safe to be around children.
It's most likely that the calcium carbonate in chalk is actually gypsum.
Chalk
Blackboard can be any shape you want. Most blackboards are rectangular.
Limestone and Chalk
Chalk dust is primarily made of calcium carbonate, a type of limestone composed mainly of calcite. It also contains small amounts of other minerals, such as quartz, clay, and mica. When chalk is used on a blackboard, the friction creates the dust that we see.
A blackboard appears black because it reflects very little light, absorbing most of the light that hits it. The dark color of the board helps to contrast with the white chalk used to write on it, making the writing clearly visible.
No, water from an area with limestone and chalk strata is more likely to be alkaline, not acidic. Limestone and chalk are composed mainly of calcium carbonate which can increase the alkalinity of water through a process called calcification.
Then you will most likely not get a job as a teacher.
Teacher
Tailor's Chalk is made from magnesium silicate or Mg3Si4O10(OH)2. Blackboard/ Chalkboard Chalk is made from calcium sulfate or CaSO4. Both were previously made from chalk a form of limestone that is a soft, white, porous sedimentary rock composed of calcium carbonate or CaCO3. Other Names for Tailor's Chalk: Sewing Chalk, Magnesium Silicate, Soapstone, Talc, Slate Other Names for Chalkboard/Blackboard Chalk: Calcium Sulfate, Gypsum, Gypsum Plaster, Plaster of Paris, Drierite, Alabaster, Anhydrite, Desert Rose * Tailor's Chalk is used to temporarily mark clothing for alterations. * Chalkboard/Blackboard Chalk is used for writing and/or drawing on a chalkboard, blackboard, slate, or enamel board. * Tailor's Chalk and Blackboard/Chalkboard Chalk are interchangeable though the method of cleanup varies if the before mentioned chalk is used for it's intended purpose or another usage. * Chalkboard/Blackboard Chalk made from calcium sulfate is dust free. * Chalk Sticks are made from calcium sulfate (calcium & sulphur molecules chemically bound to water) aka gypsum in its dihydrate form (chemical compound containing 2 molecules of water around each CaSO4 group aka calcium sulfate hemihydrate * Chalk Sticks are made through calcination. Calcination is a treatment process of removing water from a substance or compound in this case calcium sulfate by heating the calcium sulfate to a high temperature that is also below melting or fusing point causing a loss of 50% to 75% of the calcium sulfate's original moisture producing a powder. When water is then added to the powder it rehydrates and quickly hardens. * Calcium Sulfate predominately comes from Gypsum or Anhydrite though it also occurs as a byproduct of several different chemical processes * Gypsum or Anhydrite occurs in many locations worldwide as evaporites (a natural salt or mineral sediment deposit left after the evaporation of a body of water) * Pastels are made from calcium sulfate mixed with clay, oils, & pigment * Soapstone is a metamorphic rock made mostly of Talc aka Magnesium Silicate * Soapstone aka slate is what blackboards were first made from though most modern chalkboards are made with steel treated with an enamel * Chalkboards can be made any color; Blackboards refer to the original blackboards made from soapstone aka slate * Modern chalkboards are made with tiling grout; one of the main ingredients in tiling grout is Magnesium Silicate same as original Blackboards and Tailor's Chalk * In early American schools children used a slate aka soapstone pencil to write on personal slate aka soapstone boards. These slate aka soapstone pencils were a cylinder of the rock inside cedar * Slate pencils were replaced by soft chalk aka calcium carbonate (CaCO3) later replaced by calcium sulfate aka gypsum (CaSO4·2H2O)