2006-07-29 00:14:12 · 6 answers · asked by Dong N 1 in Science & Mathematics ➔ Chemistry
pH is a means of measuring the acidity/basicity of dilute solutions of substances in water.
It is defined as pH=-log[H+]
at room temperature the ionization of water
(H2O <=> H+ + OH-) has an equilibrium constant of
Kw=[H+][OH-]=10^-14.
When you add a substance that produces H+ or OH- then the concentration of the other (OH- or H+ respectively) will change so that [H+][OH-]=10^-14.
which means that pH+pOH=14 where pOH=-log[OH-]
The lowest value of pH is 0 (for [H=]=1 M). For more concentrated solutions the pH would be negative, but pH is not usefull for so concentrated acids.
Similarly the highest acceptable OH- concentration is [OH-]=1, which means pOH=0 and pH=14.
Therefore the range is from 0-14.
When a substance is neutral all H+ and OH- come from the dissociation of water. Thus [H+]=[OH-] and pH=pOH
Therefore 2pH=14 and pH=7
When the solution has 0
At different temperatures the Kw changes and thus the range of the pH-scale and the value for neutral solutions also change accordingly (range is 0-pKw and neutrality at pH=0.5pKw, where pKw is -logKw)
2006-08-01 04:57:40 · answer #1 · answered by bellerophon 6 · 0⤊ 0⤋
The pH scale measures which of the fallowing? B.) The concentration of hydrogen ions in answer A vulnerable electrolytic answer.. C.) is a adverse conductor of electrical energy Distilled water.. D.) incorporates solute molecules.
2016-10-01 05:33:46 · answer #2 · answered by morabito 3 · 0⤊ 0⤋
The "p" means the negative logarithm of something. pH is the negative logarithm of the Hydrogen ion concentration. A solution with a pH of 7 means that the molar concentration of hydrogen ions is 10 to the minus seven power. A solution with a pH of 6 means that the molar concentration of hydrogen ions is 10 to the minus six power, which is 10 times stronger than pH of 7. In neutral water, the hydrogen ion concentration is equal to the hydroxide ion concentration - both have molar concentrations of 10 to the minus seven power.
2006-07-29 00:43:23 · answer #3 · answered by Nick F 2 · 0⤊ 0⤋
logarithmically
ph can go as low as -1 too. ouch
every number each side of 7 has 10 times more free hydrogen or hydroxide
ph 4-10 is bearable.
some foods have ph has low as 2.5, you can eat them but they would burn your skin after a while
2006-07-29 00:20:08 · answer #4 · answered by mofuonamotorcycle 5 · 0⤊ 0⤋
if 0
pH can be known by the formula
pH= -log[hydrogen ion concentration]....
2006-07-29 09:33:34 · answer #5 · answered by rahul 1 · 0⤊ 0⤋
below seven its acidic... while above 7 until 14, its basic... most of those acidic substances has more hyrogen ions.. than basic substances... basic substance is more on hydroxyl ions...
2006-07-29 03:34:14 · answer #6 · answered by angel r 2 · 0⤊ 0⤋