Lecture
1 sections 151-15 3 .
Heat (review Chl do !! If heat
can
only one is
concurse increase in temperature - used to fuelendothermic ran, , it
↳
q = MspAT cannot cause increase in temp !
↳
AT coincides with molecular
·
con fuel endo thermic rans
vibrations L
↳
ATB ,
DH > O
↳
q nAH=
ex : Hade e Hag DHrap 40 :
to mode of water at its
vaporize a
boiling
point ,
must provide 40 mol energy
Practice Problem :
heating pure substances
-
what happens when
you put energy in
?
q(259) (4 184) (Ts-29815)
·
.
Heel -water heats it
q 7 85k5
=
.
water
begins to
panze
·
25 09
F
.
Ti 25 298. ISW
=
until
heating boiling ,
point
need 7 85k5 of
-
.
energy
Tt 373 15 :
When added to liquid
.
at its
energy is a
·
25
m = .
09
boiling points
↳ the remains constant while the substance boils
temperature
TCE Hz0g
HeDe energy added causing temp increase
·
↓ ↓
Phase change at
boiling point that energy can now only be
·
373 . 5
-.. ,
·
----
⑳
used to fuel the phase
change
298K
· ine ↳
line plateaus
> energy added (5) to convert btwn time and
time Ise
E
energy use power-
·
phase do not cause the breaking of bonds because HzU
changes is still Had
at the end of the phase
change
↳ molecules further
apart breaking IMF's ,
, Bone
IMF's we like a handshake
·
Intermolecular forces (IMFs) - forces btun
2 different molecules
·
Intramolecular forces: in the molecule off
people
itself
In
tramolecular
lot HaHig DH = pand =
436k/ma
takes energy
H20a-HzOig) DItrap
=
40 .5/mol Intermolecular
Practice Problems continue heating water
-
takes less
energy
starting with 25g H2O at 25%, 9 7 85h5 to
·
:
.
heat 100 %
↓
TE)
&neat e ,
:
(25g)(4 184g) (75k)
.
=
7 85k5
.
Evap (25g) (m2)(56 5 =
.
5
373.
⑧
·
Example how much I
(or how long
energy
:
will it take to
vaporize 25g Has
at 25 I bar ? and
15
Dequation to heat water 298 .
eneres
② equation to vaporize water added (5
③ add heats
iss
~ 189566
together
problem like this , pressure does not matter at weird pressures the BP will
#in ,
change
Heating Curve Diagram
T
important to reference = nAlvap
·
curve to know
heating phase change
E-masoDinvid
↓
how
many steps we X X19
needed g nalters
:
heating ↓ Attraporization
Altrap is
very MusoDsaid Phase
·
long because a
:
X) Change (e
neating ! ⑧
breaking all the IMFs
·
·
Altfusion
is
very endothermic X(s)
energy a (15)
1 sections 151-15 3 .
Heat (review Chl do !! If heat
can
only one is
concurse increase in temperature - used to fuelendothermic ran, , it
↳
q = MspAT cannot cause increase in temp !
↳
AT coincides with molecular
·
con fuel endo thermic rans
vibrations L
↳
ATB ,
DH > O
↳
q nAH=
ex : Hade e Hag DHrap 40 :
to mode of water at its
vaporize a
boiling
point ,
must provide 40 mol energy
Practice Problem :
heating pure substances
-
what happens when
you put energy in
?
q(259) (4 184) (Ts-29815)
·
.
Heel -water heats it
q 7 85k5
=
.
water
begins to
panze
·
25 09
F
.
Ti 25 298. ISW
=
until
heating boiling ,
point
need 7 85k5 of
-
.
energy
Tt 373 15 :
When added to liquid
.
at its
energy is a
·
25
m = .
09
boiling points
↳ the remains constant while the substance boils
temperature
TCE Hz0g
HeDe energy added causing temp increase
·
↓ ↓
Phase change at
boiling point that energy can now only be
·
373 . 5
-.. ,
·
----
⑳
used to fuel the phase
change
298K
· ine ↳
line plateaus
> energy added (5) to convert btwn time and
time Ise
E
energy use power-
·
phase do not cause the breaking of bonds because HzU
changes is still Had
at the end of the phase
change
↳ molecules further
apart breaking IMF's ,
, Bone
IMF's we like a handshake
·
Intermolecular forces (IMFs) - forces btun
2 different molecules
·
Intramolecular forces: in the molecule off
people
itself
In
tramolecular
lot HaHig DH = pand =
436k/ma
takes energy
H20a-HzOig) DItrap
=
40 .5/mol Intermolecular
Practice Problems continue heating water
-
takes less
energy
starting with 25g H2O at 25%, 9 7 85h5 to
·
:
.
heat 100 %
↓
TE)
&neat e ,
:
(25g)(4 184g) (75k)
.
=
7 85k5
.
Evap (25g) (m2)(56 5 =
.
5
373.
⑧
·
Example how much I
(or how long
energy
:
will it take to
vaporize 25g Has
at 25 I bar ? and
15
Dequation to heat water 298 .
eneres
② equation to vaporize water added (5
③ add heats
iss
~ 189566
together
problem like this , pressure does not matter at weird pressures the BP will
#in ,
change
Heating Curve Diagram
T
important to reference = nAlvap
·
curve to know
heating phase change
E-masoDinvid
↓
how
many steps we X X19
needed g nalters
:
heating ↓ Attraporization
Altrap is
very MusoDsaid Phase
·
long because a
:
X) Change (e
neating ! ⑧
breaking all the IMFs
·
·
Altfusion
is
very endothermic X(s)
energy a (15)
