henry's law?

[bananaboat]

i was just reading the mcat topics..under phase equilibria it says "henry's law"
what is this? is it more commonly called something else?

---

Members don't see this ad.

 

[bananaboat]

lol also something called "zeroth's law" under thermodynamics...any takers?

 

[kaybam20]

i was just reading the mcat topics..under phase equilibria it says "henry's law"
what is this? is it more commonly called something else?

It is a solubility law that relates solubility with pressure.



S = Kp
k = henry's constant.

I have never had any reason to use it in all my 15 full lenths and over 50 topicals , and about 30 subject kaplan tests. don't worry about it. It is another useless thing on the MCAT syllabus.

 

[kaybam20]

lol also something called "zeroth's law" under thermodynamics...any takers?

Zeroth law came about due to the stupidity of the scientits of yesteryears. After formulating the first, and second law of thermodynamics they realize that those two law depended on some thing fundermental which is Temperaure. so they came about Zeroth LAw which is just that there is Temperature. Another stupid detail on the syllabus.

 

[bananaboat]

Zeroth law came about due to the stupidity of the scientits of yesteryears. After formulating the first, and second law of thermodynamics they realize that those two law depended on some thing fundermental which is Temperaure. so they came about Zeroth LAw which is just that there is Temperature. Another stupid detail on the syllabus.

perhaps it was a bad idea for me to look at the syllabus only now. lol.

 

[DrWanahbe]

It is a solubility law that relates solubility with pressure.



S = Kp
k = henry's constant.

It's a related to the solubility of gases in liquids. It only works for those gases that do not react chemically with the solvent. Both solubility and pressure rise together. However, when temperature increases, solubility decreases. (To remember this, I always have to remember that when plants release warm water into lakes/streams, fish die because they can't get enough oxygen)

 

[superduper12]

ok EK says that henry's law is more accurate for the vapor partial pressure of a volatile solute where the solute has a low concentration.

Raoult's law is more accurate when looking at the vapor partial pressure of a solvent with high concentration.

doesn't a high solvent concentration automatically mean a low solute concentration?

It goes on to say: "one way to remember this is when the solvent concentration is high, each solvent molecule is surrounded by other solvent molecules, so it behaves more like a pure solvent. Thus the solvent vapor partial pressure is proportional to it's vapor pressure as a pure liquid; Raoult's law. When the volatile solute concentration is low, each molecule is surrounded by solvent molecules creating a deviation from the behavior of the pure volatile solute. Thus its vapor partial pressure is not proportional to its pressure as a pure substance (Raoult's law doesn't work in this case.), but is proportional to some constant; henry's law"