Suppose that you place a timer and a tiny pile of gunpowder in an absolutely rigid box. You then seal the box completely and insulate it perfectly so that no heat can flow in or out of the box. Soon the timer ignites the gunpowder and it burns to form smoke. Since the box is sealed, the smoke remains inside it. If you look into the box a few minutes later, you will find that the smoke has not converted back into the gunpowder because
A) there is not enough energy in the box to reform the gunpowder.
B) there are not enough atoms in the box to reform the gunpowder.
C) such an event, unburning the smoke to form gunpowder, is extraordinarily unlikely.
D) the basic laws of motion, otherwise known as Newton's three laws, forbid the unburning of smoke to form gunpowder.

Question

Quizplus · Accepted Answer

The transformation of smoke back into gunpowder is an example of a process that is highly improbable due to the laws of thermodynamics, particularly the second law, which implies that in an isolated system, processes tend to move towards a state of maximum entropy or disorder. Reversing the burning process would decrease entropy, which is extremely unlikely to happen spontaneously.

Suppose That You Place a Timer and a Tiny Pile