I am not entirely sure what you mean by "reversible by itself".An energy transformation is usually NOT entirely reversible. Some energy is wasted in the transformation, and (even though the energy is definitely still somewhere), you may need ADDITIONAL energy to transform it back.
Fossil Fuels
Any form of energy can be turned into another form.
Yes, any form of energy can be converted into any other form, although the conversion process is not 100% efficient and there will be some energy lost.
Potential energy.
The energy can come from just about any source of AVAILABLE energy.
It is a release of energy as heat and light during a chemical change. It is not itself any form of matter.
A Bunsen burner is an object: it is not a process of any kind.
physical change is reversible because you can undo it for example: if you fold a paper you unfold the paper. chemical chang is irreversible because if you make somthing together you could not seperate them.
Fossil Fuels
Well it depends on how you look at it. Firewood itself isn't because it isn't producing any thermal or electric energy. If you are looking at it as firewood being burned then yes it is an indirect form of solar because it is being converted to thermal energy
The energy itself is used the same way as any other energy - to heat our homes, operate electrical appliances, etc. Once such energy is converted to a useful form - usually electrical energy - it makes no difference (for the ability to use it) where the energy comes from.
Any form of energy can be turned into another form.
Ability to deform itself by compressing, elongate, or any other ways it can deform by itself or another form, but also it's ability to reform, or reshape itself back to it's original position. May lose it's elasticity over time though. Can convert into other types of energies. Such as Gravitational Energy and Kinetic Energy. Can be converted from Gravitational Energy and Kinetic Energy.
Yes, any form of energy can be converted into any other form, although the conversion process is not 100% efficient and there will be some energy lost.
I am not sure what you mean. What process is that? Any combustible fuel will work, not just coal. You can read about the thermodynamics part by looking for a description of the "Carnot engine". The process is NOT reversible; although the Carnot engine is reversible in theory, there are always losses in practice that make it irreversible; also, the fact of burning the coal is not reversible.
light energy is any visible form of energy that forms part of the electomagnetic spectum it is therefore transmitted as any form of electromagnetic wave.
Potential energy.