Whether it is a chemical or physical change in the process of long term formation of oil, coal, and

There are chemical changes as well as physical changes.

It should be a chemical change!!

Because, they are no longer the original substance!!

A substance can only be changed if a chemical change occurs.

It's definitely a chemical change, and he's generating new substance.

Coal, oil, and natural gas are formed as follows:Coal is an ancient plant buried in the ground and underwent complex biochemistry.

and solid combustible minerals gradually formed by physical and chemical changes, a solid combustible organic rock, mainly formed by biochemical action of plant remains, buried and then transformed by geological action.

The former is widely accepted, believing that oil is formed by organisms in ancient oceans or lakes after a long period of evolution, which belongs to biological sedimentation to oil and is non-renewable. The latter believes that oil is generated from the carbon within the earth's crust itself, is biologically independent, and is renewable.

The causes of natural gas are varied, the formation of natural gas runs through the whole process of diagenesis, plutonic formation, post-formation until metamorphism, various types of organic matter can form natural gas, saprolite-type organic matter is both oil and gas, humic organic matter mainly produces gaseous hydrocarbons.

Coal is formed by geological processes over a long period of time after the remains of ancient plants were buried in the ground. Oil is the remains of ancient organisms accumulated in lakes, seas, or on land, and transformed by complex biological and chemical processes under the action of high temperature and pressure. Natural gas is a gaseous hydrocarbon produced by the long-term deposition of paleontological remains underground, which is slowly converted and metamorphic and cracked.

1. The formation of coal is that ancient plants were buried in the ground before they decomposed, converted into peat, then converted into lignite, then sub-bituminous coal, then bituminous coal, and finally anthracite. The hydrocarbons produced by coal are subjected to the pressure and temperature conditions of the earth's crustal moving air to produce carbonized fossil minerals, that is, coal is plant fossils. This involves biological and geological processes over a long period of time.

2. Petroleum is formed by organisms in ancient oceans or lakes after a long period of evolution, which belongs to biological sedimentation and oil, and is not renewable.

3. Formation of natural gas: In the early stage of diagenesis (stage), in the shallow biochemical zone, the natural gas formed by the fermentation and synthesis of sedimentary organic matter by microorganisms is called biogenetic gas. It is sometimes mixed with gases formed by early low-temperature degradation.

Biogenetic gas occurs in rock formations with shallow burial, new age and low degree of evolution, and is dominated by methane-containing gas.