Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Lozia on November 22, 2007, 06:59:23 PM
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I've been struggling with this for a while now, and wikipedia etc dont seem to help, so, was just wondering. How can you tell between an acid and a base?And then a weak acid from strong acid, and weak base from strong base?
Been doing titrations recently you see and im not understandng whats happening :(
Cheers.
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Do you know what determines pH?
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Wikipedia is a robust source on this subject.
Serch acids, bases, and Acid-base_reaction_theories
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acids donate protons, bases accept protons
so if you had CH3COOH + NH3 =(equilibrium) CH3COO- + NH4+
S Acid S Base = W Base W Acid
CH3OOH is the acid because it loses a proton, becoming CH3COO- ( the conjagate base of CH3OOH)and NH3 is the base because it gains/accepts a proton becoming NH4+(conjagate acid). when you lose a proton you put a minus, when you gain one you put a plus
i am no completly sure for this but...for determining strong/weak acids and bases, I think you have to use a table. compare the acids, the side with the strong acid also has the strong base, the other side of the equilibrium equation will have the weak acid/base- the conjagates. i think that is right. but i am a dumbass that just learned this stuff 3 days ago and barely have a C in the class.
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The way I remember strong acids vs. weak acids:
I memorized these Strong Acids: Perchloric acid HClO4, Hydroiodic acid HI, Hydrobromic acid HBr, Hydrochloric acid HCl, Sulfuric acid H2SO4, Nitric acid HNO3, H3O+.
Any acids besides the ones above are WEAK ACIDS.
Ex: HCl is on the Strong Acid list so it's a strong acid.
Ex: HIO3 is a weak acid because it's not on my list.
Since there aren't that many strong acids, it's best to have them memorized to know which are strong and which are weak. Later on, I'll probably learn exactly what makes a strong acid strong..but until then..this is what helps me on the tests.