Chemistry 101

quatumrulesoverall · #91 (**permalink**) 08-11-2006

Perfectly depicted, professionally done Jay-qu.Could you bring up a bit more to all all of us Acid-Base equilibria, couldn't you ? I am so happy to friends like all of you.

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Jay-qu · #92 (**permalink**) 08-11-2006

Acid/base equilibrium hey!

Well I guess I should introduce the idea of an equilibrium constant, Kc. It is the ratio of the product of the concentrations of the products over the product of the concentrations of the reactants! which is probably better summarised in an equation rather than words, which sticking with the haber process like before:

$N_2(g) + 3H_2(g) <-> 2NH_3(g)$

$Kc = \frac{[NH_3]^2}{[N_2][H_2]^3}$ the units of which are worked out by cancelling the concentration units. In this case it would be $M^{-2}$ . The equilibrium constant can only be calculated once the equilibrium has been reached, otherwise it would be in error.

Now you are already familiar with what may be considered a strong or weak acid, this is what makes them strong or weak - the extent to which the reaction occurs.

When an acid is in solution the acid donates a proton very easily to water to make the hydronium ion.

eg water will sefl ionise itself $2H_2O(l) <-> H_3O^+(aq) + OH^-(aq)$
which gives rise to:
$Kc = \frac{[H_3O^+][OH^-]}{[H_2O]^2}$
water can be excluded from this equation because its concentration is always 1, hece:
$Kc = [H_3O^+][OH^-]$
The Kc for this reaction at room temp is $10^{-12}$

The pH of a solution is said to be:

$pH = -log([H_3O^+])$

There is some very interesting equilibrium reactions going on in your body! One is the system between Heamoglobin, oxygen and carbondioxide in your respiritory system.

I might get round to posting some more later, but right now that will have to do

Jay

quatumrulesoverall · #93 (**permalink**) 08-11-2006

As I know it should be log base of 10, or lg, u may check it up

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quatumrulesoverall · #94 (**permalink**) 08-11-2006

Another issue to raise, how could I raise my rep power, still 0 now, so sad

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Jay-qu · #95 (**permalink**) 08-11-2006

Yes log base 10, rep power will go up 1 for every 50 posts you get, and every 50 rep you get.

quatumrulesoverall · #96 (**permalink**) 08-11-2006

Just a bit adding to Jay-qu, at constant temperature 298K, the pH=pOH=7 for neutral solution, since the pKw=14, and Kw is another equilibrium constant, that calculated as Kc.(Note: p=-lg)

Michaelangelica · #97 (**permalink**) 08-11-2006

Could I just slip in a question while everone is talking
(Please don't let me interupt)

What is the difference between "Soil Wetting Agents" and Detergent?

Are they the same ?
Is one better than another?
Are they OK for the micro/macro-flora/fauna of the soil?
One (SWA) is very much dearer than the other.
Thanks

Jay-qu · #98 (**permalink**) 08-11-2006

They are the same chemically insofar as that they are both surfactants designed to reduce the surface tension of water so things will get wet better. But a detergent will also have other chemicals that help clean that could well be harmfull to soil.

Mercedes Benzene · #99 (**permalink**) 08-12-2006

Quote:

They are the same chemically insofar as that they are both surfactants designed to reduce the surface tension of water so things will get wet better. But a detergent will also have other chemicals that help clean that could well be harmfull to soil.

Mhmm. Chemical wetting agents are designed specifically for that purpose.
Detergents are generally... well... cleaing agents.