1.1.2: Acquisitive Convention
This convention refers to the sign associated with communication between a system and its surroundings. The convention describes changes as seen from the standpoint of the system. The convention guides chemists concerning the ‘sign’ of changes in thermodynamic variables
00for a given system. For example, if heat q flows from the surroundings into a system, q is positive. If thermodynamic energy U is lost by a system to the surroundings, ∆U is negative. In fact this convention is intuitively attractive to chemists. For example, when told that the volume of a system increases during a given process, then chemists conclude that the volume of the surroundings (i.e. the rest of the universe!) decreases.