Answer : The second law of thermodynamics states that not all energy is used because some amount of energy disperses as a heat.
Explanation :
First law of thermodynamic : It states that the energy can not be created or destroyed, it can only change or transfer from one state to another state.
Second law of thermodynamics : It states that all the energy are not used in the reaction because some amount of the energy is lost in the form of heat. This lost heat energy is the unusable form of energy.
This lost heat energy causes an increase in the entropy of the universe. That means there is no energy transferred due to the loss of energy.
Third law of thermodynamic : It states that the entropy of the system access a constant value as the temperature access absolute zero.
Hence, the second law of thermodynamics states that not all energy is used because some amount of energy disperses as a heat.
