Several questions about pH...

1. What exactly does pH stand for? Given pOH, it seems like the “H” stands for hydrogen, but then what does the “p” stand for?

2. A pH of 7 is neutral and I am told that practically this means that in a pure water solution there are 1/10^7 (Fluther’s interpretting neg sign as strikethrough) H+ ions in some unit of water and 1/10^7 OH- ions in the water due to disassociation. And that therefore a pH of 0 means all water molecules are disassociated. Is this right? This means that for pH 14, 1/10^14 water molecules are disassociated right?

3. Why do water molecules diassociate? It’s clear to me that very few of them do and they tend not to. Are there some external chemical forces at play here?

4. The pH of a solution can change not only from disassociation of water molecules but also by the introduction and dissolving of other chemicals into a solution…so in order for Chemical X to dissolve it has to form bonds with the water molecules which free up H+ ions and the tendency of H+ ions to be freed up is what determines whether a chemical is considered “strong” or “weak” as an acid or base. Did I get that right?

5. What else should I know about pH? Who came up with the concept? Did someone notice what these H+‘s were doing and how they effected solutions and decide to desribe it mathematically?