Work (thermodynamics) of the energy went out as heat, and how much as work. This can be summarized by saying that heat and work are not state functions of the system. This is in contrast to classical mechanics, where net work exerted by a particle is a state function. Pressure–volume work (or "PV" work) occurs when the volume of a system changes. "PV" work is often measured in units of litre-atmospheres where = . However, the litre-atmosphere is not a recognised unit in the SI system of units, which measures P in Pascal (Pa), V in m, and PV in Joule (J),
Scientific law water); although in many systems (notably biomacromolecules and minerals) the ratios tend to require large numbers, and are frequently represented as a fraction. More modern laws of chemistry define the relationship between energy and its transformations. Scientific law The laws of science, also called scientific laws or scientific principles, are statements that describe or predict a range of natural phenomena. Each scientific law is a statement based on repeated experimental observations that describes some aspect of the Universe. The term "law" has diverse usage in many cases (approximate, accurate, broad, or narrow theories) across all fields of natural science (physics,