If energy or mass can neither be created nor be destroyed then how is there electrical energy and potential energy and everything in the world possible?

Energy can transfer (convert) from one form to other.

Explanation:

Law of Conservation of Energy : It states that energy can neither be created nor destroyed in a chemical reaction but can be converted from one from to another.

Potential Energy(P.E) : Energy possessed by the object due to its position and size.Near the ground it attains zero value or close to it.

Kinetic Energy(K.E) : The energy possessed by the object due to its speed .When the object is in motion it has kinetic energy

For example :

When a stone is placed (rest) at some height on the top of the building . It has only potential energy .The potential energy at this point is calculated by

P = mgh

Now , when the the stone is released. It falls to the ground . During its motion towards the ground , its speed increases but the distance of stone from the ground decreases .

Hence the Object in between the ground and building has both K.E and P.E

K.E + P.E = mgh + 1/2 mv^2

If the object reaches just near the ground. Its kinetic energy is maximum but potential energy is almost zero . So at this point ,

K.E = 1/2 mv^2

Hence the Same potential energy is converted into kinetic energy while reaching the ground .

The object itself has not created the energy in between the motion.Neither its energy goes to zero.

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

the dissolution of polymer can be thermodynamically described in 2 steps.