QP and chemistry

[mississippichem]

Does this mean, for example, that some (small amount of) heat is generated when substances dissolve into a solution?

 

Yes, now you're thinking chemically! Just remember that these interactions are WAY stronger than gravity.

[lemur]

Yes, now you're thinking chemically! Just remember that these interactions are WAY stronger than gravity.

That is why a drop of undissolved dye at the bottom of a glass of water will leech upward through the water, no, even if its density is greater than or equal to the water, right? I guess another way to look at it would be to say that gravity is the force of attraction that remains between electrostatic systems after they have organized to the point of maximum entropy and thus charge-neutrality. Still, there must be SOME level of electrostatic attraction that is weaker than gravity in some situation, no?

 

Also, it raises the question of what happens to chemical reactions in stronger gravity fields. Does gravity create a threshold of electrochemical reactivity by maintaining pressure/heat/energy levels above that which would allow weaker chemical bonds to form? Maybe I'm diverging too much from the thread topic with that, though.

 

 

[Horza2002]

Essentially, a solute is soluble in a solvent if there is a net stabilisation (i.e. the solute-solvent interactions are more favourable than solvent-solvent interactions). In the case of NaCl dissolving in water, the interactions between the water molecules and the ions are more stable than those between water molecules.

 

Yes, when a solute dissolves in a solvent, there is indeed energy released. Its is normally refered to as the "enthalpy of dissolution" and is often negative (i.e. favourable). A drop of dye in the bottom of a glass of water will slowly move upwards because of diffusion. Tbh, im not sure if gravity will have that much of an effect on chemical reactions....the mass of molecules is soooo tiny that gravitational effects are not used even when doing extremely sensitive calculations.

[lemur]

Tbh, im not sure if gravity will have that much of an effect on chemical reactions....the mass of molecules is soooo tiny that gravitational effects are not used even when doing extremely sensitive calculations.

I didn't mean gravity between the atoms/molecules in the chemical reaction. I meant gravity levels in the gravity well where the reaction is taking place. In other words, if you had a chemical reaction taking place among a collection of particles floating together far from any gravity well, they might be able to interact with lower levels of ionization than if they were in a gravity well. E.g. if you had a cup of some chemicals on the moon, the particles in the cup would be compressed against each other with a certain amount of force due to gravity that they wouldn't have compressing them if they were being compressed at a lower level of gravity. It's just a thought insofar as gravitational force builds up in a gravity well whereas it's practically irrelevant among individual atoms/molecules.