If you want a high-tech, presbyopia-correcting intraocular lens for your cataract procedure, then costs would increase to an average of about $4,591 per eye (vs. $4,461 in 2010, $4,337 in 2011, $4,269 in 2012 and $4,350 in 2013).
When Î´S is negative and Î´H is negative, the relative magnitudes of Î´S and Î´H determine if the reaction is spontaneous. Low temperatures make the reaction more favorable. When Î´S is negative and Î´H is positive, a process is not spontaneous at any temperature, but the reverse process is spontaneous.A spontaneous process is the time-evolution of a system in which it releases free energy (usually as heat) and moves to a lower, more thermodynamically stable energy state. spontaneous process is capable of proceeding in a given direction, as written or described, without needing to be driven by an outside source of energy.
Driving Forces and Gibbs Free Energy. Some reactions are spontaneous because they give off energy in the form of heat (H < 0). Others are spontaneous because they lead to an increase in the disorder of the system (S > 0). Calculations of H and S can be used to probe the driving force behind a particular reaction.