Please help The following transition occurs at a molecular level for a substance. What transition corresponds to this change in microscopic structure? The carbon dioxide molecules on the left are in a regular, tightly packed pattern. After heating, it becomes much lower density. A. Melting B. Boiling C. Sublimation D. Freezing

Solid tin exists in two forms: white and gray. for the transformation sn(s, white) → sn(s, gray) the enthalpy change is -2.1 kj/mol and the entropy change is -7.4 j/(mol*k). a. calculate the gibbs free energy change for the conversion of 1.00 mol white tin to gray tin at -30℃. b. will white tin convert spontaneously to gray tin at -30℃? c. at what temperature are white and gray tin thermodynamically equivalent at a pressure of 1 atm?