Which two energy transformations are shown in the photo? A. Chemical energy → electromagnetic energy B. Chemical energy → thermal energy C. Thermal energy → electrical energy D. Thermal energy → chemical energy

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.