Why does a ballon filled with helium rise while a ballon filled with an equal volume of average atmospheric Air does not

A balloon inflated with helium has less total mass than the air it displaces; its weight (and average density) also are less. Therefore the force exceeds the weight force, the net force on the balloon is upwards, and the balloon rises.

Ur e n d is not real

The internal energy of the system we can term it as total potential energy and kinetic energy. energy flows out of the surrounding from the system then we can say that the internal energy of the final state is lower than its initials. the sign of  δesystem is negative.δesystem = efinal - einitial=-ve  efinal  ∠einitial.