Question
Download Solution PDFLimestone, chalk and marble are different forms of ______.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFThe correct answer is Calcium carbonate.
Key Points
- Calcium carbonate and its forms:
- In nature, calcium carbonate occurs in the forms of chalk, limestone, and marble.
- Limestone, chalk, and marble are all sedimentary rocks that are composed mainly of calcium carbonate.
- Limestone is a sedimentary rock that forms from the accumulation of calcium carbonate shells and skeletons of marine organisms.
- Chalk is a soft, white, porous rock that is made up of the microscopic remains of marine plankton.
- Formation:
- The skeletal remains of dead sea animals sink to the seabed. Over millions of years, layer build-up and pressure from the top layer changes the bottom layer into chalk.
- Earth movements due to earthquakes lift the layer of chalk to the Earth's surface.
- The earth's movements can also cause the layers to sink further. Thus, high pressure and heat cause the chalk to turn into much harder limestone.
- The limestone deposit may stay below the Earth for a longer time and due to higher pressure and temperature, the limestone turns to marble.
Additional Information
- Calcium Oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical compound.
- It is a white, caustic, alkaline, crystalline solid at room temperature.
- Calcium phosphate [Ca3(PO4)2] is fundamental to the formation of teeth and bone.
- Calcium phosphate is a calcium salt of phosphoric acid. It is also known as Calcium phosphate tribasic or Tricalcium Phosphate.
- Calcium Hydroxide [Ca(OH)2] is also known as Slaked lime.
- It is a white powder or colourless crystal which is obtained when quicklime (calcium oxide) is mixed with water.
Last updated on Jun 6, 2025
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