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pH, important but not easy subject

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

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pH, important but not easy subject

Postby Philippe » Fri Jan 07, 2005 3:49 pm

Hello everyone,

my name is Philippe and I'm studying to become a biology and chemistry teacher in secondary school in Belgium.

My first classes in chemistry are going to be about pH, acids and bases. I would really like to give out interesting stuff. Like how and why did this guy Sorensen 'invent' the pH scale; why do strong acids burn skin and not the weak ones (how does [H30+] attack metals, skin, paper,...); the importance of pH in stuff around us,... . If you could help (by droping down a good site,...) it would really help me out! (I ve already spent a few hours on the net without success!)

Take care -
Philippe
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Postby biostudent84 » Fri Jan 07, 2005 9:25 pm

You're in luck! Before deciding to switch to pre-med, I was a chemistry major.

pH is a simple way of measuring the concentration of H+ ions. With pH is pOH, which measures the concentration of OH- ions. When the pH and pOH of any substance is added together, it will always result in 14.

You confuse the word "strong" acid with "concentrated" acid.

A concentrated acid is a substance that has a very low pH.

A strong acid is an acid in which the H+ ion separates from the rest of its substance completely when placed in water. Examples of this are Hydrogen Iodide, Hydrogen Bromide, Hydrogen Chloride, Hydrogen Chlorate, Hydrogen Nitate, Hydrogen Sulfate...or respectively, Hydroiodic Acid, Hydrobromic Acid, Hydrochloric Acid, Nitric Acid, and Sulfuric Acid.

All other acids are weak acids, as they do not undergo "complete dissacosiacion in water."

Any strong or weak acid can cause acid burn if concentrated enough.

And remember, a base burn can also occur. My chemistry mentor has a half-dollar sized burn from Sodium Hydroxide on his foot that's very sickening to look at. A base burn is potentially more dangerous than an acid burn because bases do not trigger your nerves to sense pain when it comes in contact. You could have a base burn on your back and not know about it for days because you would never feel the pain.
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Postby Philippe » Mon Jan 10, 2005 7:06 pm

Hello again,
Ok thanks a lot for your help, very kind!
See ya round
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