What quantity of limestone, upon heating, will give 56 kg of CaO?

Limestone (Chemical formula: CaCO3), upon heating, produces lime or calcium oxide (chemical formula: CaO) and carbon dioxide. The reaction can be represented by the following chemical equation:

`CaCO_3 (s) + heat -> CaO (s) + CO_2 (g)`

Here, 1 mole of limestone produces 1 mole of carbon dioxide and 1 mole of lime or calcium oxide. 

The molar mass of limestone is 100 g (= mass of Ca + mass of C + 3 x mass of O = 40 + 12 + 3 x 16). Similarly, the molar mass of lime is 56 g.

Thus, we can also say that 100 g of limestone produces 56 g of lime.

Or, 1 g of lime is produced by 100/56 g limestone.

Thus, 56 kg of lime will be produced by 100/56 x 56 kg = 100 kg.

So, in order to obtain 56 kg of lime, we need to heat 100 kg of limestone.