627501
Acids, Bases and Constants
- Orders of reaction
- 1st order
- rate of reaction is
directly proportional
to the concentration
of substance
- Rate=k[X]
- rate of reaction is
directly proportional
to the concentration
of substance
- 2nd order
- Rate of reaction is directly
proportional to the square
of the concentration of the
substance
- Rate=k[X]^2
- Rate of reaction is directly
proportional to the square
of the concentration of the
substance
- 0th order
- Rate of reaction is not proportional to
the concentration of the substance, but
the substance is still necessary for the
reaction to take place
- Rate=k[X]^0
- Rate of reaction is not proportional to
the concentration of the substance, but
the substance is still necessary for the
reaction to take place
- Rate
determining
step
- The slowest step in
the reaction is what
is considered the
rate determining
step.
- the other steps are so fast comparatively, that
to concentrations of the reactants have no
overall effect on the rate of reaction
- the other steps are so fast comparatively, that
to concentrations of the reactants have no
overall effect on the rate of reaction
- The slowest step in
the reaction is what
is considered the
rate determining
step.
- 1st order
- Kc
- General Formula: aA + bB <--> cC
dD Kc= ([C]^(c)[D]^(d) / [A]^(a)[B]^(b)
Kc is the equilibrium constant
- the Kc for a reaction is
constant if temperature
is constant
- Changing
concentrations of
reactants/products
in equilibrium will
have no effect on
the value of Kc
- is the concentration of one of
the substances is changed,
then the position of
equlibirum will shift to
produce more on the other
side of equation, until a new
dynamic equilibrium forms
with the same Kc
- is the concentration of one of
the substances is changed,
then the position of
equlibirum will shift to
produce more on the other
side of equation, until a new
dynamic equilibrium forms
with the same Kc
- Pressure also has no
effect on Kc, for the
same reasons that
concentration doesn't
- When Kc is greater than one. Then
the position of equilibrium, moves to
the RHS. When it is below one, it
moves to the LHS
- Kc value changes with
temperature, because temperature
causes the concentrations of the
reactants/products to change
- General Formula: aA + bB <--> cC
dD Kc= ([C]^(c)[D]^(d) / [A]^(a)[B]^(b)
Kc is the equilibrium constant
- Acids and bases
- in
bronsted-lowry
theory, bases
are proton
acceptors, and
acids are proton
donors
- When an acid
dissolves into water,
it disassociates into
positive hydrogen ion
and a negative ion.
HA<--->H+ + A-
- strong acids fully
disassociate into ions
- strong acids fully
disassociate into ions
- Ph is a measure of
the concentration of
H+ ions in solution.
Ph= - Log10[H+]
- Ka is the disassociation
constant for acids. Kc=
[H][A]/[HA]
- For every acid,
there is a value
of Ka which is
constant
- the higher the Ka
value, the stinger the
acid (a perfect strong
acid would have an
infinite Ka value)
- there is also the extra
value of pKa, which has
the same relationship as
with pH. The higher the
value of pKa, the weaker
the acid
- there is also the extra
value of pKa, which has
the same relationship as
with pH. The higher the
value of pKa, the weaker
the acid
- For every acid,
there is a value
of Ka which is
constant
- Kw is the water dissociation
constant. it is always 10^(-14)
- Kw=[OH][H]
- pKw=pH +pOH
pKw=14
- Kw=[OH][H]
- Buffer solutions
- A buffer solution is a mixture
of a weak acid and its
conjugate base (which usually
comes from a salt). this
resists a change in pH when
small amount of acid/alkail
are added
- when a acid is added, it increases [H+]
which reacts with A-, and shift equilibrium
to the left. When an alkali is added, it
reacts with the few H+ ions to produce
water. This reduces the concentration of
H+ causing the equilibrium to shift to the
right, to restore the lost H+ ions
- when a acid is added, it increases [H+]
which reacts with A-, and shift equilibrium
to the left. When an alkali is added, it
reacts with the few H+ ions to produce
water. This reduces the concentration of
H+ causing the equilibrium to shift to the
right, to restore the lost H+ ions
- The Ph of buffer solutions can
be worked out. But be aware
that H+ does no longer equal A-
- A buffer solution is a mixture
of a weak acid and its
conjugate base (which usually
comes from a salt). this
resists a change in pH when
small amount of acid/alkail
are added
- in
bronsted-lowry
theory, bases
are proton
acceptors, and
acids are proton
donors
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