2470883
Description
Mind Map by Amy Holden, updated more than 1 year ago
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Created by Amy Holden
over 9 years ago
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Acid and Bases
- Acid-base theories
- Lewis
- Acid - electron pair
acceptor
- Base - electron
pair donor
- Acid - electron pair
acceptor
- Bronsted-Lowry
- Acid - proton
donor
- Base - proton
acceptor
- Acid - proton
donor
- Lewis
- Conjugate systems
- Acids are related to bases
- ACID <=> PROTON + CONJUGATE BASE
- ACID <=> PROTON + CONJUGATE BASE
- Bases are related to acids
- BASE + PROTON <=> CONJUGATE ACID
- BASE + PROTON <=> CONJUGATE ACID
- For an acid to behave as an acid, it must have a base present to accept a proton
- acid + base <=> conjugate base + conjugate acid
- HA + B <=> BH+ + A-
- HA + B <=> BH+ + A-
- acid + base <=> conjugate base + conjugate acid
- Acids are related to bases
- pH = -log10[H+]
- The smaller the pH,
the greater the conc. of
H+
- The smaller the pH,
the greater the conc. of
H+
- pOH = -log10[OH-]
- Kw = [H+][OH-]
- water is weakly
dissociated
- water is weakly
dissociated
- Weak acids and bases
- weak acids and weak bases
dissociate only in aqueous
solution
- Ka = ([H+][A-]) /
[HA]
- Ka is the dissociation constant
for a weak acid
- Ka = [H+]2 /
[HA]
- Ka is the dissociation constant
for a weak acid
- The weaker the acid..
- the less it dissociates
- the fewer ions you get
- the smaller Ka
- the less it dissociates
- pKa
- very weak acids have very small Ka values
- Its is easier to compare the strength as pKa
- Its is easier to compare the strength as pKa
- pKa = -log10 (Ka)
- very weak acids have very small Ka values
- weak acids and weak bases
dissociate only in aqueous
solution
- species that can act
as an acid or base
are amphoteric
- Strong acids
- a strong acid is one which dissociates
completely in water into H+ and A-
- Examples
- HCl
- HNO3
- H2SO4
- HCl
- Strong acids do not dissociate
fully at high concentrations
- There is not enough water
- diluting the acid tenfold causes the
pH to increase by one unit
- There is not enough water
- a strong acid is one which dissociates
completely in water into H+ and A-
- Titrations
- Curves
- Indicators
- Curves
- Buffers
- A solution that resists
change of pH when small
amounts of acid or base
are added or on dilution
- Acidic buffers
- They are made from a mixture of a
weak acid and a soluble salt of
that acid
- It will maintain a pH
of below 7
- The weak acid component is to act as a
source of HA to remove any added OH-
- HA + OH- --> A- + H2O
- HA + OH- --> A- + H2O
- The salt component is to act as a
source of A- to remove any added H+
- A- + H+ --> HA
- A- + H+ --> HA
- They are made from a mixture of a
weak acid and a soluble salt of
that acid
- It is possible to saturate a buffer
- Basic buffers
- It will maintain a
pH of above 7
- They are made from a
mixture of a weak base and a
soluble salt of that base
- Aqueous ammonia and ammonium
chloride acts as a bsic buffer
- NH3 + H+ --> NH4+
- NH4+ + OH- --> NH3 + H2O
- NH3 + H+ --> NH4+
- It will maintain a
pH of above 7
- A solution that resists
change of pH when small
amounts of acid or base
are added or on dilution
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