Change in Internal Energy by Work Video Lecture | AP Chemistry - Grade 9

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part 7 hello friends this video on turn
would talk about adiabatic system the
only tool adiabatic wall is wall where
through which you can transfer the heat
or transfer the energy and the matter
between the surrounding system so at
every system is nothing but a system
where it is does not a lot this does not
allow we have explained this I think is
a closed system actually is nothing but
a closed system which does not allow the
exchange of heat between the system and
the sound this bond is called adiabatic
and as I told anybody causes the process
there is no transfer of heat between the
system in the surrounding so I just want
to tell you that adiabatic and
isothermal are two different things
so if you see adiabatic is an idea by
adiabatic in my second one two different
thing an idea by dick there is no
exchange of heat is all totally isolated
in isothermal we maintain same
temperature T's constant temperature has
to become maybe you have to supply extra
heat also it if required the temperature
has to be gone that is isothermal
adiabatic is totally isolated somewhere
don't transfer any heat to the system 1
he just transferred transistor so as I
told the internal energy change it can
be done by the work done on the system
or by system or the heat transfer they
told now and also internal change
constant volume thing so since it is
constant volume is a critical concept I
have again put it here just to remind
you that when you talk about internal
energy change you talk about constant
water so let us list it as the first
method where we talk about internal
change by work so let us take a divided
system 2
be on safe side so and that's why I
discussed the idea basis last line so
there are various ways to change the
internal energy of the system by going
world the first can be you char this you
add each on then you turn into actually
using something in flow system you turn
it with some mechanical thing I'll show
you one device at Lee which scientists
are using in this chart use Chartres you
do some mechanical work and that
mechanical work will be converted into
heat energy sorry internal energy or you
read this in the rod so you put some
internal rod here you put some internal
rod here and you heat this with some
internal lot but the electric energy in
first case you are churning it it was
churning it second case you are putting
some heaters or what you can do is you
can put some chemicals here which react
and form heat so you can see you want to
change the internal energy of this kind
of system with a volunteen do it two by
three into one more also I can think of
only three base now maybe we can think
of more ways you can turn this you do
some mechanical energy on this you can
heat it you spa some electric energy you
can do some chemical reaction the
presence of chemical energy so in all
these case here the internal energy of
the system will change we'll have some
interesting okay and since this is an
adiabatic thing there is no heat
transfer there is no heat transfer from
outside to system or system to Sarang
there is no heat loss there is no it
easy so my change in internal energy
will be nothing but the work done
adiabatic whether you would double by
churning you heating you're using
chemical reaction we mix
all the idea wedding work is nothing but
my change in attorney this is what I
think is it possible I'm just telling
you can you believe me you have to why
because a scientist has done this so
James Prescott Joule the jewel word came
from Haran a very famous scientist with
a rich guy Ashley was owning a be a
breeding breeding or factory village
time he did this experiment his he was
able to show that the given amount of
work done on system no matter how it is
done you would charted you put some
e-rod didn't chemical reaction doesn't
matter how you do the work of the system
it produces the same change of state and
that state of change he measured using
temperature change
he is very difficult to change the and
that part-time find all the internal
change
he didn't focus only on a temperature
change to focus up and what he did was
he had this begin the adiabatic walk
instrument and he had this churning
device right
this is churning device and tied to a
thread and it is rotated like this so
what happens is if you put a mass here
the mass falls down there is a change in
potential energy of this mass and this
potential is your this this footage has
changed this was the height H MGH is
transferred using this threaded transit
a chance does it produce some I mean
there's a mechanical energy is
transferred and this increases the
energy of this system it's closed
please note so constant volume and this
is thermally attached and with this he
was able to see a change in temperature
and indeed using lot of other ways maybe
he he tried up the heater or he tried it
ride various options on he tried three
different ways I believe he tried the
heat so after no she tried
the this this oh she kinda more approach
and he saw in all of these keys change
internal energy is same doesn't matter
which path for although his a experiment
we're not accepted that time but later
on it was accepted and we found that
whatever he observed was true
so that means Michigan path before does
it matter and that's why you see the
vogner is my path function depicting the
path but that change IntelliJ is not a
path much because this games let's prove
that you want to change the internet you
may change by various paths it will be
the rod you Chan it you do some chemical
reaction change the energy is same
implies that work done by all these
things are same okay so that's what the
jewel has done James Prescott Joule you
show that no matter which path you
follow if the work done system is same
it will have same energy change I
explain this again earlier also I'll
explain once again the sign condition of
internal energy so it is positive if the
work done is is on the system that means
system you do all call the system of the
system gets energy right you doing a
walk on system system becomes pressure
and the Delta U is paused
if system is doing some work system will
becoming weak system is losing energy
right if work is done by system the
Delta U is negative okay if system is
doing some worse will becoming being so
the change in energy is negative if
people are doing work on system systems
become greater and Delta u s---based
if we talk about various units of work
so in CGS unit the work has expressed
ERG s herbs in SI unit it doesn't choose
and one duelist in the bar seven dogs
and it's also in a lot of mathematical
problem will see that you will have
something volume we talk about baggage
over P Delta V will have this formula
operation will duvall you so the
pressure will be atmospheric in pressure
ATM and the volume will be later so we
will get something later at more ATM and
you want to convert in the Joule you see
that one liter ATM is nothing but 101.3
June and the pressure is in bar then you
get something a liter bar and then you
will see that one liter bar is hundred
joules so we'll use this these two in
fact these two generally for numericals
but generally we will try to convert
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