Strong acid vs weak acid [ENDORSED]
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Strong acid vs weak acid
What is the defining feature to know if something is strong acid or a weak acid?
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Re: Strong acid vs weak acid
A strong acid is one that is completely ionized in solution, whereas a weak acid can have a reverse reaction. Some common strong acids are HCl, HNO3, H2SO4, HBr, HI, HClO4, and HClO3. These were just strong acids I was taught to remember in high school, but I'm not sure there is any other way to quickly identify.
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Re: Strong acid vs weak acid
A strong acid will completely ionize in solution, whereas a weak acid will not and it is actually reversible.
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Re: Strong acid vs weak acid
What makes a strong acid completely ionize or disassociate as opposed to a weak one?
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Re: Strong acid vs weak acid
On a side note, one defining feature to determine the difference is the number of arrows in the chemical formula (one means that it is a strong acid or base, while two half-headed arrows mean that it is a weak acid or base). It’s because the strong acid/base dissociates completely. However, someone asked this question in class, and Dr. Lavelle said that some textbooks have both arrows for strong acids in the chemical formula with one of them being more defined (lengthier) than the other.
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Re: Strong acid vs weak acid
Helen Shi 1B wrote:What makes a strong acid completely ionize or disassociate as opposed to a weak one?
Strong acids have mostly ions in solution, therefore the bonds holding H and A together must be weak. In other words, strong acids easily break apart into ions allowing them to completely dissociate in contrast to a weak acid.
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Re: Strong acid vs weak acid
Does the strength of acids and bases relate in anyway to electronegativity differences or ionization energy?
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Re: Strong acid vs weak acid [ENDORSED]
• STRONG ACID PRODUCES MORE PROTOS IN SOLUTION THAN A WEAK ACID
• STRON ACIDS ALMOST COMPLETELY IONIZED IN SOLUTION. HCl, HBr, etc.
• CALCULATIONS INVOLVING STRON ACIDS (OR BASE):
APPROXIMATE BY ASSUMING 100% IONIZED (DISSOCIATED)
THEREFORE 0.1M HCl (Aq) IMPLIES 0.1M H3O+(Aq) AND 0.1M Cl- (Aq)
WHAT IS THE pH?
pH = log10 [H+] (CONCENTRATION OF H+); pH = 1
• WEAK ACIDS ARE INCOMPLETLY IONIZED IN SOLUTION.
WE HAVE TO SETUP AN EQUILIBRIUM CONCENTRATIONS:
A--H(Aq)A-(Aq) + H+(Aq)
K= [A-]*[H+]/[A*H]
E.g ACETIC ACID, MANY CH3COOH MOLECULES AND A SMALL PROPORTION OF ACETATE, CH3COO- (RATIO 100:1)
• STRON ACIDS ALMOST COMPLETELY IONIZED IN SOLUTION. HCl, HBr, etc.
• CALCULATIONS INVOLVING STRON ACIDS (OR BASE):
APPROXIMATE BY ASSUMING 100% IONIZED (DISSOCIATED)
THEREFORE 0.1M HCl (Aq) IMPLIES 0.1M H3O+(Aq) AND 0.1M Cl- (Aq)
WHAT IS THE pH?
pH = log10 [H+] (CONCENTRATION OF H+); pH = 1
• WEAK ACIDS ARE INCOMPLETLY IONIZED IN SOLUTION.
WE HAVE TO SETUP AN EQUILIBRIUM CONCENTRATIONS:
A--H(Aq)A-(Aq) + H+(Aq)
K= [A-]*[H+]/[A*H]
E.g ACETIC ACID, MANY CH3COOH MOLECULES AND A SMALL PROPORTION OF ACETATE, CH3COO- (RATIO 100:1)
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