You are given a dark shiny solid and asked to determine whether it is iodine or a metallic element. Suggest a nondestructive test that would enable you to arrive at the correct answer
2/10/2016 Entropy and Free Energy - Entropy (a.k.a. randomness) and heat energy combine into concept of free energy to explain processes that occur Spontaneous Processes - Any process that occurs w/o input of additional energy (i.e. w/o outside intervention) Ex: A ball rolling down a hill. - It doesn’t matter how fast the process occurs. Ex: The slowing of Earth’s rotation over millions of years. Ex: ◦ CH 4 2O → 2O + 2H 2 ∆H 2 rxn= -892kJ (exothermic) o Very slow reaction H + HO → H O ∆H ◦ = -56.2kJ (exothermic) 2 rxn - Almost all exothermic reactions (when ∆H is negative) are spontaneous. o But endother
