Cheat Sheet for Chemical Equilibrium, Cheat Sheet of Chemical Principles

Download Cheat Sheet for Chemical Equilibrium and more Cheat Sheet Chemical Principles in PDF only on Docsity! Cheat
Sheet
for
Chemical
Equilibrium:
 Equilibrium
 • Rates
are
equal.
 • Concentrations
remain
constant.

 
 Finding
Keq

 • Keq
=
products
 
























reactants
 • You
can
have
Kc,
Kp,
Ksp,
Ka,
Kb

These
are
the
same
as
Keq.
They
just
describe
specific
types
 of
reactions.
 • Given:

Concentrations.

Asked
for
Keq,
solve
for:

Kc.
 • Given:

Pressures.
Asked
for
Keq,
solve
for:

Kp.
 • Given:
Grams.
Asked
for
Keq
and
it
is
not
clear
which
to
use…

 o If
you
have
a
reaction
of
gases,
solve
for:
Kp.
 o If
you
are
a
reaction
with
aqueous
solutions,
solve
for:
Kc.
 • Sometimes
you
are
asked
to
solve
for
Kc
and
then
relate
to
Kp.
You
use
Kp
=
Kc(RT)∆n
 
 Finding
Keq
when
the
reaction
is
changed:
 • When
a
reaction
is
reversed,
the
new
Keq
=
(1
/
Keq)
 • When
a
reaction
is
multiplied,
the
new
Keq
=
(Keq)n
where
n=
the
number
the
equation
is
 multiplied
by
 • When
more
than
one
reaction
is
added
together
(like
a
Hess’s
Law
problem),
your
Keq
for
each
 reaction
will
be
MULTIPLIED
together.
New
Keq
=
(K1)*(K2)
 
 Determining
The
Direction
a
Reaction
Proceeds
 • K
>
1:
Production
of
the
products
is
favored.
Equilibrium
lies
to
the
right.
 • K
<
1:
Production
of
the
reactants
is
favored.
Equilibrium
lies
to
the
left.
 • Reaction
Quotient,
Q,
for
non‐equilibrium
conditions
 o Q
=
K,
System
is
at
equilibrium
 o Q
>
K,
Too
many
products,
system
shifts
to
the
Left
to
increase
production
of
reactants
 o Q
<
K,
Too
many
reactants,
system
shifts
to
the
Right
to
increase
production
of
products
 
 ICE
Charts
 • Completed
using
Concentrations
or
sometimes,
Partial
Pressures
 • Given:
Initial
Concentration
of
Reactants
only‐
Products
will
be
zero.
Determine
the
change
by
 subtracting
“x”
from
reactants
and
adding
“x”
to
products.
 • Given:
Initial
Concentrations
of
Products
only‐
Reactants
will
be
zero.
Determine
the
change
by
 subtracting
“x”
from
the
products
and
adding
“x”
to
reactants.
 • Given:
Initial
Concentration
of
a
species
and
Equilibrium
concentration
of
a
species:
Determine
 the
change
by
subtracting
equilibrium
concentration
and
initial
concentration.
Fill
in
table
as
 appropriate.
 • Don’t
forget
to
consider
mole
ratios
when
determining
the
change
of
other
species.
 • Keq
is
determined
from
equilibrium
values.
 • All
ICE
charts
you
see
on
the
AP
exam
follow
the
5%
rule.
That
means
when
you
subtract
“x”
 or
add
“x”
from
a
concentration
other
than
0,
you
can
ignore
it!