11/24/06

Thoughts \ Developed Thoughts \ Rants \ Raves \ Writing

10/29/2004 15:36 -0500 GMT

Oil and Water

So hydrocarbons, when dropped into the polar environment of water, will add order to the whole system. What do you mean they will add order to the system? Well, you’ve got a glass of water, with happy little H₂Os floating around, hydrogen bonding four times each (ideally) all over the place, flowing freely. Add that hydrocarbon, and suddenly the waters recognize a foreigner (a non-polar species) and they stiffen up. They get all soldierly and have to line up just so, so that as few of them as possible will be next to that nasty looking non-polar species. They tend to arrange themselves away from the hydrocarbon, and arranging, in any form, is a decrease in entropy. Chaos decreases for the time that the hydrocarbon is present.

That is a decrease in entropy, or “- ΔS”. In the thermodynamics equation ΔG = ΔH – TΔS, if you insert that decrease in entropy or “- ΔS”, you’re going to come up with a ΔG = ΔH –(T*(- ΔS)). A negative times a negative is a positive, and ΔG will = ΔH + the product of T and the absolute value of ΔS. Easier said is this, Δ G = Δ H + TΔS. We learned earlier that ΔG is compatible with life only when it is negative. In other words when the free energy of a system is negative, then it is giving off energy – it is alive. If it is positive, then it is receiving energy, but not giving it out. It’s inanimate.