1.6.3 The Lime Cycle

• What type of rock is limestone?

  Sedimentary rock
• What is the chemical name for quicklime?

  Calcium oxide
• What are the two primary methods for forming calcium carbonate?

  Natural and industrial
• Steps in the lime cycle

  1️⃣ Heating limestone in a kiln to produce quicklime (CaO)

  2️⃣ Reacting quicklime with water to form slaked lime (Ca(OH)₂)

  3️⃣ Allowing slaked lime to react with carbon dioxide to reform calcium carbonate (CaCO₃)
• The lime cycle demonstrates how limestone can be converted to other useful forms of lime through heating and chemical reactions.
• Match the method of calcium carbonate formation with its description:

  Natural Formation ↔️ Marine organisms use calcium and carbon dioxide to build shells.

  Industrial Formation ↔️ Carbon dioxide reacts with calcium hydroxide in carbonation.
• Heating limestone in a kiln produces calcium oxide and carbon dioxide.
• Calcium oxide, also known as quicklime, is used in the production of cement, glass, and steel
• What is the chemical name for quicklime?

  Calcium oxide
• Match the process with its key details in the formation of calcium carbonate:

  Natural Formation in Marine Environments ↔️ Marine organisms absorb calcium and carbon dioxide from seawater.

  Industrial Formation ↔️ Carbon dioxide reacts with calcium hydroxide in carbonation.
• The reaction of quicklime with water releases heat.


  True
• What is the product of heating limestone in a kiln during the first step of the lime cycle?

  Calcium oxide
• The lime cycle describes the series of chemical reactions that occur when limestone is heated and then reacted with water.

  True
• What is the chemical name for slaked lime?

  Calcium hydroxide
• Calcium carbonate is formed through natural processes in marine environments and industrial reactions with carbon dioxide
• What is the industrial process called that forms calcium carbonate by reacting carbon dioxide with slaked lime?

  Carbonation
• What is the balanced chemical equation for the reaction of quicklime with water to form slaked lime?

  \ce{CaO(s) + H2O(l) - > Ca(OH)2(s)}</latex>
• Quicklime is used in steel production to remove impurities like sulfur and phosphorus
• The heating of limestone in kilns releases carbon dioxide, contributing to greenhouse gas emissions
• Limestone is primarily composed of calcium carbonate.
• Calcium hydroxide is also known as slaked lime.

  True
• Calcium carbonate is naturally formed in marine environments by organisms like coral and plankton.
• What happens when limestone is heated in a kiln?

  It forms quicklime and CO₂
• What are two industrial uses of calcium oxide?

  Cement and glass production
• The key steps in the lime cycle

  1️⃣ Heating limestone in a kiln

  2️⃣ Reacting quicklime with water

  3️⃣ Allowing slaked lime to react with carbon dioxide
• The reaction between slaked lime and carbon dioxide regenerates limestone.


  True
• The reaction between quicklime and water to form slaked lime is an exothermic reaction
• Match the use with the chemical and explanation:

  Construction ↔️ CaO: Used in cement production by reacting with water and aggregates.

  Agriculture ↔️ Ca(OH)₂: Neutralizes acidic soils for plant growth.

  Water Treatment ↔️ Ca(OH)₂: Neutralizes acidic water and precipitates heavy metals.
• What is the primary chemical composition of limestone?

  Calcium carbonate
• When limestone is heated in a kiln, it produces calcium oxide, also known as quicklime
• Match the process with its description in the formation of calcium carbonate:

  Natural Formation in Marine Environments ↔️ Marine organisms build shells and skeletons from calcium carbonate

  Industrial Formation ↔️ Carbon dioxide reacts with slaked lime
• Heating calcium carbonate in a kiln produces calcium oxide and carbon dioxide
• What are some common uses of slaked lime?

  Construction, agriculture, water treatment
• Why is slaked lime used in agriculture?

  Neutralizes acidic soils
• What is the chemical equation for the industrial formation of calcium carbonate?

  \ce{CO2 + Ca(OH)2 - > CaCO3 + H2O}
• Quicklime reacts with water to form slaked lime.


  True
• The lime cycle involves a series of chemical reactions starting with limestone and ending with its reformation.


  True
• When quicklime reacts with water, it forms calcium hydroxide, also known as slaked lime
• What are the products of heating limestone in a kiln?

  Calcium oxide and carbon dioxide
• In which industry is quicklime used to produce cement?

  Construction