What Do The Letters Ph Stand For?
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hollanda88
Fish Addict
i believe its the partial pressure of H+ ions (Hydrogen ions)
correct me if im wonrg
edit: its pH too don't know why lol
OP
OP
wonrg should be wrongi believe its the partial pressure of H+ ions (Hydrogen ions)
correct me if im wonrg
there you go, I corrected you
partial pressure of hydrogen ions. wouldn't that be PPH. That sounds wierd doesn't it, what is the PPH of the water
hollanda88
Fish Addict
wonrg should be wrongi believe its the partial pressure of H+ ions (Hydrogen ions)
correct me if im wonrg
there you go, I corrected you
partial pressure of hydrogen ions. wouldn't that be PPH. That sounds wierd doesn't it, what is the PPH of the water
lol well imm laying on my back and supposed to be writing my 10,000 word dissertation lol hope i haven't spelt anything wrong in that.
pH is on a log scale so a change of 3 on the pH scale is a 1000 times difference in h+ ion conceptration. Acidity is the ammount of free H+ ions in the solution thats why carboxylic acids can buffer because they can donate of recive H+ ions from or into the water.
andrew
bagu
Shouldn't you be looking to the right?
done this today
it means
percentage/potential hydrogen
as you go more acidic in the pH scale, you have more Hydrogen+ ions.
it means
percentage/potential hydrogen
as you go more acidic in the pH scale, you have more Hydrogen+ ions.
hollanda88
Fish Addict
done this today
it means
percentage/potential hydrogen
as you go more acidic in the pH scale, you have more Hydrogen+ ions.
Yet the number goes down oooooooooooooo spooky lol
Ph is calculating the logarithm of hydrogen ions in solution...there is also a pOH...isn't chemistry fun!
Miss Wiggle
Practically perfect in every way
I've heard both 'Potential Hydrogen' and 'Power (of) Hydrogen' quoted
whatever it is I know the 'p' does not stand for another chemical as it is pH not PH.
whatever it is I know the 'p' does not stand for another chemical as it is pH not PH.
hollanda88
Fish Addict
I've heard both 'Potential Hydrogen' and 'Power (of) Hydrogen' quoted
whatever it is I know the 'p' does not stand for another chemical as it is pH not PH.
Yeah, although many people quote the p as different things throughout my degree I have always understood it to be referanced to as partail pressure as this is how most gaseous elements are measured and as Hydrogen is gaseous at room temps but does disolve I think thats why a lot of people think its partial pressure. I have heard of power and other but don't think there that scientific therfore may not be what it originally stood for.
andrew
OohFeeshy
It's only forever; not long at all...
pH means -log[H+], or the log to the base 10 of the concentration of hydrogen ions (protons) in moles per decimeter cubed.
It's a convenient way of measuring how strong an acid is- the more hydrogen ions that become dissociated in solution, the stronger the acid.
You can also have pOH, which is the log of the concentration of OH- ions, and is handy for working out the pH of alkalis.
It's a convenient way of measuring how strong an acid is- the more hydrogen ions that become dissociated in solution, the stronger the acid.
You can also have pOH, which is the log of the concentration of OH- ions, and is handy for working out the pH of alkalis.
pH is indeed potential of Hydrogen. A lot of the first experiments where the nature of pH was determined involved electrochemistry, and the terminology just kind of stuck even though it turned out not to be electrical and the equations aren't exactly the same. There is a little similarity in that an electron e- plus a hydrogen ion H+ combine to form a neutral atom -- so when electrochemistry was being worked on (which involves the flow and use of e-) they just thought that the way H+ acted would be similar. I don't think that they had realized how buffers work, and the fact that water disassociates.
As posted above, it is probably just best thought of as a function. Just like if we wrote f(x) = cos(x), where now f() stands for "take the cosine of whatever is inside the ()'s", the p in pH stands for "take the negative of the base 10 logarithm of the concentration (in moles per Liter) of whatever comes after the p". Also, it is properly written pH -- little p, big H, not big P big H.
Don't confuse the notion of a partial pressure, which is used primarily in gas mixtures, and the p used in liquid mixtures. They use the same symbol, but are very different concepts. The p in pH has nothing to do with how much hydrogen gas dissolves in water. The partial pressure comes into play when doing gaseous mixtures in equilibrium because the partial pressure of a substance in the gas can almost always be taken as the activity of that substance in the gas. In liquids, the activity is of course a strong function of the mole fraction of the item, but the activity coefficient is usually also a strong function of temperature, pressure, and how the constituents of the liquid behave. And, in ionic mixtures, how many ions are in the mixture can play a role, too, often called the "ionic strength". The only way the partial pressure may play a role in liquid systems is if you are calculating a vapor-liquid equilibrium. Then, maybe both the partial pressure and the pH of the liquid could be important!
As posted above, it is probably just best thought of as a function. Just like if we wrote f(x) = cos(x), where now f() stands for "take the cosine of whatever is inside the ()'s", the p in pH stands for "take the negative of the base 10 logarithm of the concentration (in moles per Liter) of whatever comes after the p". Also, it is properly written pH -- little p, big H, not big P big H.
Don't confuse the notion of a partial pressure, which is used primarily in gas mixtures, and the p used in liquid mixtures. They use the same symbol, but are very different concepts. The p in pH has nothing to do with how much hydrogen gas dissolves in water. The partial pressure comes into play when doing gaseous mixtures in equilibrium because the partial pressure of a substance in the gas can almost always be taken as the activity of that substance in the gas. In liquids, the activity is of course a strong function of the mole fraction of the item, but the activity coefficient is usually also a strong function of temperature, pressure, and how the constituents of the liquid behave. And, in ionic mixtures, how many ions are in the mixture can play a role, too, often called the "ionic strength". The only way the partial pressure may play a role in liquid systems is if you are calculating a vapor-liquid equilibrium. Then, maybe both the partial pressure and the pH of the liquid could be important!
/en.wikipedia.org/wiki/Ph
Its not the first time that I have seen wiki wrong and probably won't be the last. As Dr. Honkerface said, it is the negative log, not some obscure relative scale that is indexed by samples of varying pH as wiki would have you believe.
OohFeeshy
It's only forever; not long at all...
The Wiki article isn't wrong, just a lot more technical. pH is a heap more complicated than '-log[H+]'- for a start, you can't exactly have a concentration of H+ since it's just a proton which has no hope of existing alone in solution.
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