DNA is the genetic material of almost all the living organisms but exceptions are involved in case of some viruses that contains RNA as their genetic material.
The DNA consists of the nitrogenous base, dexoyribose pentose sugar and the phosphate group. The base is attached with the sugar on the 1' position. The phosphate group is linked with the sugar at 5 position of the dexoyribose sugar.
If a piece of charcoal is taken and set on fire it will evolve CO2 and heat. Charcoal is solid but carbon dioxide is gaseous. This is an example of change of state and evolve of heat during chemical reaction.