Limestone

Limestone is a sedimentary rock found in the earth.  It is formed from the shells of dead sea creatures which become crushed and buried at the bottom of the sea, when these creatures die.

Limestone is made up of the chemical calcium carbonate, CaCO₃.  It is a metal carbonate. The following YouTube video is from the Scientific Eye series and explains the importance of limestone and the issues related to it.  You might be expected to discuss the social, economic and environmental of extracting and using limestone.

Limestone can undergo reactions as part of the 'Limestone cycle'.  The first step is a thermal decomposition, this is where a substance is broken down into smaller compounds using heat. The ease with which they decompose varies within a group. The higher up the reactivity series a metal is, the more stable its carbonate will be, so the least reactive metals have the carbonates that decompose most readily. Looking at group 2 magnesium carbonate decomposes relatively easily, calcium carbonate requires significant heating to decompose. As you go further down the group the metal carbonates become more stable and less easily decomposed by heat.