Are fuels contain potential energy

Answer 1

Potential energy is energy something has because of its position (for example, a ball high in the air or a magnet held apart from another magnet)

Fuels contain chemical energy, which is actually a type of potential energy...

After you have burnt the fuel, the products (like carbon dioxide or water) contain the same atoms as the fuel did, but they are arranged in a different way. This new way of arranging the atoms contains less energy, and the left-over energy is changed to heat and light.

The reason that different arrangements of atoms contain different amounts of chemical potential energy is that the electrical charges (positive and negative) are spaced out differently, attracting or repelling each other. For example, two positive charges close together "want" to move away from each other, so they have electrical potential energy.

This means that chemical energy is really potential energy.

To take it a stage further: A Chemistry teacher will tell you that if you weigh all the stuff you are left with after burning (ash, gases and smoke), together it will weigh exactly the same as the stuff you had before burning (fuel and oxygen). That is not quite true! In fact, a tiny tiny tiny bit of mass (stuff) has been lost. This is because all potential energy is really mass. When the fuel burns, a tiny bit of its mass is changed to light and heat energy. All the light and heat coming out is made like this. A lot more mass changes to energy in a nuclear reaction.

You only need a miniscule amount of mass to make a huge amount of energy (a nuclear bomb changes about 3kg (7lb) of matter into energy.