Μηχανική

22 Φεβ 2014 (πριν από 4 χρόνια και 4 μήνες)

221 εμφανίσεις

The Man Behind the Mole

By Haley Streeter and Minna

K.

Amedeo
o

Born:

August 9
th
, 1776

Died: July 9th,

When His Hypothesis Became Generally Accepted: After

ecclesiastical law

at the age of 20. Soon after,
he dedicated himself to

*positive philosophy and in 1809 started
teaching it at a

high school in

property
. *Ecclesiastical or Canon Law is the body of codified laws governing the affairs of a Christian church *Physic
s a
nd Math
to have been both well
-
educated and religious. He
married Felicita Mazzé and had six children.

He served in the courts during the French occupation
and the

Restoration. His passion was for the study of
physics and mathematics, which he pursued first as an
amateur.

law

(sometimes
referred to
as

hypothesis

or
principle) is a

gas law
named after

Amedeo
.

He hypothesized
that two given
samples of an

ideal
gas,
same

temperature,

pressure
and

volume, contain
the same number
of

molecules.

Scientific Research

V

is
the volume of the gas.

n

is the

amount of substance

or Mole

of the gas.

K

is a
proportionality

constant.

A proportionality
constant is two quantities
that have a constant
ratio.

Mathematic Form:

V

____ = K

n

Amedeo Avogadro is usually known for his
Dalton had this idea before Lussac
and

Avogadro, but both Dalton and Lussac
thought it was incorrect.

?
Avogadro’s inspiration was Dalton’s ideas of
gases and atomic weights.

Introduced the basic unit called the mole

Discovered that equal volumes of all gases at the same
temperature and pressure contain the same number of
chemical units

We now know that a mole contains 6.022137 x 10
23
atoms or molecules of a single type of substance (known

His scientific papers and essays have gained him a
reputation as a major contributor to the atomic theory
of matter

Avogadro’s number not only helps us to determine
molar mass but also to indirectly determine atomic mass

Chemistry was just beginning to become an exact
science. The Law of Definite Proportions and the Law of
Multiple Proportions were well accepted by 1808, at
which time John Dalton published his New System of
Chemical Philosophy.

In order to understand the
ideas being developed at this
time.

In 1811, Avogadro published an article in

Journal de physique

that
explained the difference between molecules and atoms. He pointed
out that Dalton had confused the concepts of atoms and molecules.
The "atoms" of nitrogen and oxygen were really "molecules"
containing two atoms each.

CONTRIBUTIONS EXPLAINED

AMEDEO’S

EXPERIMENT

During the nineteenth century, it was
possible to create reasonable estimations
measurements of colloidal particles.

In the twentieth century, Mullikan's oil drop
experiment was more accurate than the
original experiment , therefore was used

Explanation of Experiment

Lussac demonstrated that the
particles in a gas are not in
contact with each other and
actually make up only a very
small

fraction

of the gas itself.
Most of the gas is empty

space
.
So the size and shape of atoms
in the gas are irrelevant.

suggestion to clarify
Lussac's

results.
Consider a case with
water. Lussac showed that: two
volumes of hydrogen + one
volume of

oxygen

= two
volumes of water.

IMPOSSIBLE

So…why is it ‘Impossible’?

The same result can be
expressed as:
two
particles of hydrogen
(H
H
) + one particle
of

oxygen

(O) = two
particles of water (H
-
O
H
-
O
)
. (At the time,
water was thought to
consist of one

atom

of
hydrogen and one
atom of

oxygen.)

Because you
cannot begin
with one particle
of

oxygen

and
end with two.

suggested is that the smallest
particle of an element can
sometimes consist of

two
atoms joined together in a
molecule
, a term he invented
for the new particle.

If the smallest particle of

oxygen

is
a

molecule

of

oxygen, we can explain Gay
-
Lussac's results as follows: two particles of
hydrodgen

(H
H
) + one particle
of

oxygen

(O
-
O) = two particles of water
(H
-
O
H
-
O
).

In 1811, Amedeo first
proposed that the volume of
a gas (at a given pressure and
temperature) is proportional
to the number
of

atoms

or

molecules

regardl
ess of the nature of the gas.
The French physicist

Jean
Perrin

in 1909 proposed
naming the constant in honor

One mole of carbon is
6.022 x 10
23

atoms of
number).

Because they are so small, atoms and molecules cannot be
counted by the human eye. Instead, we’ve developed a
bunch of indirect ways. The mole is important to us scientists
because it connects the world that we can’t see to the world
we can measure. The number will of course depend both on
the formula of the substance and on the weight of the
sample. But if we consider a weight of substance

that is the
same as its formula (molecular) weight expressed in grams
, we
have only one number to know:

,
6.022137
×

10
23
, usually designated
by
N
A
.

The work of Avogadro was almost completely
neglected until it was forcefully presented
by

Stanislao

Cannizarro

at the Karlsruhe
Conference in 1860. He showed that Avogadro's
Principle could be used to determine not only
molar masses, but also, indirectly, atomic masses.

His Influence

expanded and improved
on Dalton's atomic theory.
For a number of reasons,
however, his ideas were
largely ignored for half a
century. Not until
Stanislao

Cannizarro

1850s did chemists finally
them

Avogadro’s Law is one of the most
fundamental principles of Chemistry and
it allows to make every calculation with
whatever amount of atoms or molecules
in order to study and balance chemical
reactions. It was stated in 1811 by the
-
1856) and it affirms that:

"Equal volumes of gases at the same
pressure P and

temperature

T contain
the same number of atoms or molecules,
regardless their chemical nature and
physical properties".

He was very influential. His
discoveries still have an impact
on chemistry.

known for his Law and Number

both named after him.

Did you know that an Avogadro's number of
standard soft drink cans would cover the
surface of the earth 200 miles deep?

number of
unpopped

popcorn kernels, and
spread them across the U.S., the country
would be covered in popcorn 9 miles deep?

If you could count at a speed of 10 million
atoms per second it would take you 2 billion
years to count up to all the atoms in a mole?

Thank You For

1.
Sarti
Amedeo."

Italy: A Reference Guide
from the Renaissance to the Present
,
European Nations. New York: Facts
On File, Inc., 2004.

Modern World
History Online
. Facts on File,
Inc.

http://www.fofweb.com/activelin
k2.asp
? (Accessed October

16,

2010).

2.

Anne Marie
Helmenstine
, Ph.D.

October 17, 2010.

Chris Johnson.

The Man.
October 17, 2010.
http://www.bulldog.u
-

Amedeo
.
October

17, 2010.
http://www.chemheritage.org/discover/chemistry
-
in
-
history/themes/the
-
path
-
to
-
the
-
periodic
-

Reference List

Sources

Contributor:

Melvyn C.
Usselman
, Ph.D., Professor of Chemistry, University of Western Ontario.

Usselman
Amedeo
."
World Book Student.

World Book, 2010. Web. 17 Oct. 2010.

Sarti
Amedeo
."
Italy: A Reference Guide from the Renaissance to the Present
, European Nations. New York: Facts
On File, Inc., 2004.
Modern World History Online
. Facts On File, Inc.

ItemID
=WE53&iPin=ITA0078&SingleRecord=True

(accessed October

16,

2010).

http://www.bulldog.u
-

e/index.html&usg=__ObVtSiHv2gCBrrwrBhw7z33LJLs=&h=220&w=119&sz=8&hl=en&start=0&sig2=ON40DTbhhgMl0U0vpj16BQ&zoo
m=1&tbnid=ZlicAmDA7vF1aM:&tbnh=161&tbnw=87&ei=pnG6TJOrIYWssAP7zZzPDw&prev=/images%3Fq%3Dscientific%2Bmole%26
hl%3Den%26biw%3D1152%26bih%3D651%26gbv%3D2%26tbs%3Disch:1&itbs=1&iact=hc&vpx=532&vpy=136&dur=2033&hovh=176
&hovw=
95&tx=75&ty=135&oei=pnG6TJOrIYWssAP7zZzPDw&esq=1&page=1&ndsp=17&ved=1t:429,r:2,s:0

efurl=http://www.brooklyn.cuny.edu/bc/ahp/AVC/MacroInv/Protein/VCB_Protein_Inv.html&usg=__xzMvdPtQjgfvt_A3DKamrkdiOFE
=&h=300&w=200&sz=33&hl=en&start=54&sig2=AwQne4jxL1sapp54l0QUsw&zoom=1&tbnid=dEOyhtG4CnQcCM:&tbnh=167&tbnw=
gbv%3D2%26tbs%3Disch:10%2C1643
&itbs=1&iact=hc&vpx=715&vpy=232&dur=4035&hovh=240&hovw=160&tx=73&ty=166&oei=8n
K6TPjqO4KcsQOPp9HkDg&esq=4&page=4&ndsp=16&ved=1t:429,r:8,s:54&biw=1152&bih=651

stkate.edu

http://reich
-

2) Animated Mole:
http://www2.waterforduhs.k12.wi.us/staffweb/Sciencefolder/Mole%20Day/MOLE_DAY_E
XPLOD.gif

3) Whack

a…:
http://www.lynnclassical.org/lynn%20images/DSCN0481.JPG

4)Mole
Antonelliana
:
50px
-
Mole_Antonelliana01.jpg

5) Mole With Pencil:
http://metevil.tripod.com/moleday/pencilmole.jpg

6) Mole of Fortune:
http://www.holidayforeveryday.com/wp
-
content/mole_of_fortune_2.jpg

7) Animated Mole:
http://www2.waterforduhs.k12.wi.us/staffweb/Sciencefolder/animated%20gifs/morty_mol
e_in_hole_lg_clr.gif