Significant figures - Some Basic Concepts of Chemistry Video Lecture - Class 11

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please note let's understand this topic
called significant figures now it's very
significant in chemistry so let's play a
little attention here the uncertainty in
the experiment or any careful values is
indicated by mentioning the number of
significant figures I'll tell you what
it is it talks about precision these are
the digits which I know will certainly
it talks about listen I'll tell you why
but before that let's have some rules to
write significant figures it sees that
all the nonzero digits are significant
figures for example I have number 3 to 5
8.2 all these non digit numbers they'll
be a significant in this case they are
four significant figures all the nonzero
digits are significant zeros proceeding
to the first non zero are non
significant example you say 0.28 they
suppose is zero zero point two eight so
in this case these are non significant
but these are significant zeros between
two nonzero significance our signal was
a velocity three zero three five
so this guy is also part of signaling in
them correct zeros at the end of the
right numbers are significant to where
they are
on the right side of a decimal point for
example I have 23 point zero zero two or
twenty three point zero zero zero so
here these are significance I'll tell
you why because when I'm talking about
later bosz twenty three point zero zero
that means I am talking about these
positions I'm talking about I can talk
about something called twenty three
point zero one I can talk about
something called twenty three point nine
one right
that means these values I can talk about
and that's why these are significant
knowledge but I am talking about it
suppose twenty three point zero that is
I am only interested in twenty three
point one or what is the point two
not talking about right is a point zero
one okay because this is the precision
of the instrument I'm talking about
twenty three point zero zero that means
I can talk about when it went zero one
zero to twenty two point nine five eight
seven so that means these values are
critical right so if I have point here
and if I have numbers here then they are
significance and exact numbers have
infinite number of significant figures
example I have 23 that has infinite
numbers because you can write 23 as 23.0
the rosary in finite number sense right
so that means it is has infinitum along
anything that the rules are this but
it's understand significant figures are
used false this isn't and they are
meaningful digits which are known with
certainty you are sure that this is it
exists correct and you say twenty three
point eight seven you are sure about all
this
we'll take some examples on this
significant figures for example you say
point zero three this guy has one
finishing in together why the a I can
I'd L 3 into 10 to power minus 2 this
guy is only one sin even figures correct
but I got zero point two zero zero this
guy has pleased indeed why because if
I'm talking void point to this guy will
have one but if I talking point to zero
they will have two from Roy Moore point
two zero zero this guy will have three
see why it does drawing one point two
zero zero that means I can also talk
about point two zero one point zero zero
two point two nine eight or eighty seven
these values also I can talk about let's
say I'm talking about point zero zero
here point two zero zero I can also talk
about these values that means these
numbers are also known this certain 80
right then telling point two zero zero
that means I know it is fine to zero
zero in the scale they make is never
been another point two zero one the
these numbers are also known as utility
so these are three significant games if
you talk about thirty two point zero one
this
for some Universal because I can talk
about thirty two point zero to thirty
four ninety five right so these plus
this if I add one more zero here law it
will have five why because I'm talking
about thirty two point zero one zero I
can talk about twenty two point zero one
one also correct if I talk about
something concept twenty-three this is
really infants individual why because
I'm I can talk about twenty three point
zero zero zero also because I am shuttin
that this is 2300 shape correct that's
how you find us example you have zero
zero zero point zero zero two seven
eight this guy has only seasonally why
because I can I des 2 point 7 into 10 to
the power minus one degree so only three
seen it a triggers correct and if 0 is
between for example I have two three
zero eight point seven one so in this
case there's one two three four five six
he had done the examples in class ten
this I am revisiting into that you can
understand more significant figures
plays a critical role and that's why I'm
taking this topic it will make T let us
stick some rules of addition and
subtraction for addition it says that
the result cannot have more than more
digits the lights it with decimal points
then that either of the original numbers
for example I have to multiply twelve
point one month into eighteen point so
Adam I'm adding it plus 18.0 the website
like this twelve point one one then 18.0
one point zero one to cut now you see
the least decimal is one after decimal
point if you add these you get thirty
one point one to two but your answer
should be thirty one point one by
because the least number is once well
I'm bar only about the least significant
figures
why because logically or it makes sense
right because I am concerned only about
numbers one zip number off a decimal
because it is 18.0 even if it is if I'm
talking about 18.0 even if it is
eighteen point zero five 18.04 eighteen
point zero three eighteen point zero to
80 point zero one eighteen point zero
zero but all these case I will write
even point zero
why because I am taking only one digit
after it so the final addition should
also have only one does it's this guy's
only three only three this is after
point but I haven't bothered only about
one does it so I'll take thirty one
point one answer so the rulers the
result cannot have more digit to the
right of the decimal point then either
although personal so the minimum here
was one so I took one sale early for but
it will never be the same thing in the
inner operation if you see the result ma
must be reported with no more than
significant figures as they are in the
measurement with few significant example
you have this you multiplied two point
five with one point two five what you
get is three point one two five right
but in this case if you see there is one
number so I am not bothered about one to
five here I'm only about three point one
white because 3.125 will round off to
three point one if you take only one
number after the decimal right and why I
am doing this because one of the numbers
involved in the multiplication was only
for two significant figures they are
only two significant hairs so will take
only two significant figures here so in
multiplication division addition
subtraction so all my inputs you the
rule is you have the inputs for example
you have a BCD phone numbers even if you
might add you find the least significant
figures of this listening indicates the
a B or C D your answer they'll also be
the least the logic says that if you are
not bothered about two significant
figures in two point five while both
Lebon in
output so in output also in the
production also I am not bothered about
3.125 these desserts are more modern and
more only about three point one hope you
understand this the lodge again you have
ABCD numbers you add also you find the
least significant numbers of these
example this guy has two so your output
will also have to sing in figures seen
for multiplication
A to B into C into B so let suppose this
guy is three this guy's for this guy's
five in this case once an even bigger so
the output will also have only one
significant figures correct that's how
it let's take some examples the question
is how many significant figures are
there in the following equations so if
you see this guy point zero zero two
five a night as 2 point 5 into 10 to the
power minus 1 2 3 this guy has to
sitting in tears to 0-8 I can say that
it has 3 sneakers also I can say it has
infinite significant use correct 5:05 it
has you can say 4 significant figures or
infinite 1 to 6 triple 0 here I can
ignore this part because I can write
this guy's 10.26 into a bar fight so
this guy is only 3 singing videos we
talk about 500 dot 0 this guy's force
moving it goes 1 2 3 plus 0 is because
I'm baack I can talk about five point
five zero zero point one I can talk
about five zero zero point two like that
I can talk about this so this guy's also
significant here because points are
invention two point zero zero three boom
this guy is facing me because I can talk
about two point zero zero three five
three six so this means it has five
significant figures correct so we have
to round this guys to the next three
significant figures so that means I
would take 3 1 2 is already there this
guy will be 3 right does actually move
these two three point two one six thirty
four point two one six so two one six if
we round off it becomes two that is
man's ten point four one zero seven this
becomes n point four why because four
if you're not there becomes four if this
has been ten point four six one let's
suppose then I could have written ten
point five okay rounding doc says it is
six ever made into five but since it is
one here I am keeping it for correct
this guy point zero zero four six five
nine
this guy will become zero point zero one
two three significant so I will begin
for six because five nine become six
correct those guys not because I need
only crease Indian figure so this guy is
my three significant takers four seasons
please note if you make it zero point
four six zero zero this is forcing the
rainmakers one two three four I need
only three what's the question so I will
make it zero point four six two eight
zero eight this is for cinnamon because
I have to make it three I'd remove one
this becomes 2 8 1 PI 2 8 1 0 because I
am looking only for C so this guy has
three significant figures if you see two
point eight one into 10 to the power 10
trees in the fingers because my job is
to convert this guy into 3 this was
forced in Ian's figures but I am looking
for three so I made it to eight oneself
hope you understand this question how
many see the Mian figures should be
present in the answer of the college you
see this guy the first one this guy has
four this guy has two right and this
survey is infinite and this guy has one
so the minimum of them is 1 so answer
everyone so I'll take the one part so
this guy will have one significant
takers correct you talked about this
this guy is infinite this guy's for slim
computers so that the answer will be
half for cinema tickets for take out
this question this guy is 1 2 3
this guy's 1 2 3 4 this guy's 1 2 3 so
this is
we'll have three significant how because
we take the minimum right this guy is
three this guy's Ford is the s3 but
we'll take the William so this way we'll
have three significant correct we always
take the minimums off the significant
figures when I talk about multiplication
division addition oh now I understand
dimension analysis so often we see that
in calculating in to convert system from
one even smaller right so there's a
method to accomplish this right this
fact this method is called factor level
method or unit vector method or
dimension analysis where we convert
students from one system to example we
have two liter of milk I want to convert
this into meter view because I have
calculation where I have convert this
guy into this guy for example I have
this opposed meter per second some speed
I have to convert this into kilometer
per hour
I have something in meter I have to
convert into kilometer dual-screen of
conversions for those things mini
dimensional analysts and it's helpful in
converting one unit of system of units
from one system to another unit they
explain some examples in this thank you
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