Sign of DG for Spontaneous processes
DGo < 0 for all SPONTANEOUS processes
?STOTAL = ?Ssystem + ?Ssurroundings > 0
2nd LAW requirement for SPONTANEITY is :
Multiply by T T?Ssystem + T?Ssurroundings > 0
and ?Ssurroundings = ?Hosystem/T
Thus T?Ssystem - ?Hosystem > 0
Multiply by -1 (->reverse > to <), drop subscript “system”