Acids and Bases

Water

Water (H₂O) is a covalent compound of hydrogen and oxygen.
Randomly and spontaneously, a water molecule will naturally break apart (disassociate) into one H⁺ and one OH^- ion.
On average, one out of every 555 million H₂O molecules will disassociate.
These ions will soon spontaneously recombine only to be replaced by another H₂O disassociating.
This process is on going and is at equilibrium (balanced).
We measure the number of H⁺ ions with the power Hydrogen scale (pH).
The pH scale ranges from 0 to 14. The lower the number, the higher the number of H⁺ ions present.
If we are balanced (same number of H⁺ and OH^- ions) the pH = 7.0
Pure water has a pH = 7.0

An acid produces H⁺ ions when dissolved in water.
Acids increase the number of H⁺ ions, the pH reading will go down.
With a strong acid most of the molecules come apart (disassociate) to form H⁺ ions.
In a weak acid only a few molecules disassociate.
Acids have a sour taste.
Examples of common acids:
- milk = 6.4
- tomato juice = 4.8
- 'pure' rain = 5.6
- stomach acid < 3
- worst acid rain = 1.8
- battery acid = 1.5

A base produces OH^- ions when dissolved in water. The pH will rise.
With a strong base most of the molecules come apart (disassociate) to form OH^- ions.
In a weak base only a few molecules disassociate.
Bases have a bitter taste and feel slippery (makes soaps with your skin oils).
Examples of common bases:
- human blood = 7.4
- sea water = 7.8
- ammonia = 11.9
- lye = 13