Under standard conditions (298 K and 1 atm), which statement is true? diamond spontaneously converts to graphite graphite spontaneously converts to diamond none of the above How can the spontaneity of the reaction be reversed? increase temperature decrease temperature none of the above
Answer
Reaction: C(diamond) -> C(graphite) For this reaction, delta H is -1.9 kJ and delta S is 3.3 J/K. What matters are the signs of these values. Since H is negative and S is positive, the conversion reaction from diamond to graphite is spontaneous at all temperatures. Diamond spontaneously converts to graphite, and the change in temperature does not affect the spontaneity.
So the answer is A, C.