chemical reactions & mole concept 10th std chemistry
TRANSCRIPT
In Chemistry the mole is a
fundamental unit in the “SystèmeInternational
d'Unités”, the SI system, and it is used to measure
the amount of substance.
This quantity is sometimes referred to as the chemical amount. In Latin
mole means a "massive heap" of material. It is convenient to think
of a chemical mole as such.
Visualizing a mole as a pile of particles, however,
is just one way to understand this concept. A sample of a substance
A sample of a substance has a mass, volume (generally
used with gases), and number of particles that is
proportional to the chemical amount (measured in moles)
of the sample.
Measuring one of these quantities allows the calculation of the
others and this is frequently done in
stoichiometry
The mole is to the amount of substance (or chemical amount) as
the gram is to mass. Like other units of the SI system, prefixes can
be used with the mole, so it is permissible to refer to 0.001 mol as
1 mmol just as 0.001 g is equivalent to 1 mg
Formal Definition
According to the National Institute of Standards and Technology
(NIST), the Fourteenth ConférenceGénérale des Poids et Mesures
established the definition of the mole in 1971
The mole is the amount of a substance of a system which contains as many
elementary entities as there are atoms in 0.012 kilogram of carbon-12; its symbol is "mol." When the mole is
used, the elementary entities must be specified and may be atoms,
molecules, ions, electrons, other particles, or specified groups of such
particles
Elementary Entities
In particle physics, an elementary particle or
fundamental particle is a particle not known to have
substructure; that is, it is not known to be made up of smaller
particles
If an elementary particle truly has no substructure, then it is one of the basic
building blocks of the universe from which all
other particles are made
In the Standard Model, the elementary particles consist of
the fundamental fermions (including quarks, leptons, and
their antiparticles), and the fundamental bosons (including
gauge bosons and the Higgs boson).
Historically, the hadrons (mesons and baryons
such as the proton and neutron) and even whole
atoms were once regarded as elementary
particles• [email protected]
(Indeed, the word "atom" means "indivisible".) A central feature in elementary particle theory is the
early 20th century idea of "quanta", which revolutionized the understanding of electromagnetic
radiation and brought about quantum mechanics
For mathematical purposes, elementary particles are normally treated as point particles, although some particle theories such as
string theory posit a physical dimension
According to the Standard Model, all
elementary particles are either bosons or fermions (depending on their spin)
The spin-statistics theorem identifies the
resulting quantum statistics that
differentiates fermions from bosons
According to this methodology: Particles normally associated
with matter are fermions. They have half-integer spin and are divided into twelve flavours.
Particles associated with fundamental forces are bosons
and they have integer spin• [email protected]
Elementary fermions (matter particles):
Quarks: up, down, charm, strange,
top, bottom
Leptons:
electron, electron neutrino, muon, muon
neutrino, tau, tau neutrino
Elementary bosons (force-carrying particles):
Gauge bosons: gluon, W and Z bosons,
photon
Other bosons Higgs bosonOf these, only the Higgs boson
remains undiscovered, but efforts are being taken at the
Large Hadron Collider to determine whether it exists or
not
Additional elementary particles may exist, such as the graviton, which would mediate gravitation. Such particles lie beyond the
Standard Model
Common elementary particlesSeveral estimates imply that practically
all the matter, when measured by mass, in the visible universe (not
including dark matter) is in the protons of hydrogen atoms, and that roughly
1080 protons exist in the visible universe (Eddington number), and
roughly 1080 atoms exist in the visible universe.
Each proton is, in turn, composed of 3
elementary particles: two up quarks and one down
quark
Neutrons and other particles heavier than protons, as well as
helium and other atoms with more than one proton, are so
rare that their total mass in the visible universe is much less
than the total mass of protons in hydrogen atoms
Lighter particles of matter, although equal (electrons) or
vastly more (neutrinos) numerous than protons, are so much lighter than protons, that
their total mass in the visible universe is again much less than the total mass of all
protons.• [email protected]
Some estimates imply that practically all the matter, when
measured by numbers of particles, in the visible universe (not
including dark matter) is in the form of neutrinos, and that roughly 1086 elementary particles of matter exist in the visible universe, mostly
neutrinos• [email protected]
Some estimates imply that roughly 1097 elementary
particles exist in the visible universe (not including dark
matter), mostly photons, gravitons, and other
massless force carriers• [email protected]
Standard Model
The Standard Model of particle physics contains 12 flavours of
elementary fermions, plus their corresponding antiparticles, as well as elementary bosons that mediate the forces and the still
undiscovered Higgs boson
However, the Standard Model is widely considered to be a provisional theory
rather than a truly fundamental one, since it is not known if it is compatible
with Einstein's general relativity
There are likely to be hypothetical elementary
particles not described by the Standard Model, such as the
graviton, the particle that would carry the gravitational force or the sparticles, supersymmetric
partners of the ordinary particles
The 12 fundamental fermionic flavours are
divided into three generations of four
particles each
The remaining six are leptons, three of which are
neutrinos, and the remaining three of which have an
electric charge of −1: the electron and its two cousins,
the muon and the tau• [email protected]
Hope you have got a basic idea about matter,
particles and its fundamental constitution
now
