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MOLE- symbol- mol
It is often more convenient for us to group objects into
defined units of measurefor calculations.
Units of Measure
For example cement and sand are usually measured in standardised
measuring pots or by standardised dices having a known and commonly
agreed weight.
Countable V Uncountable
Roses and pebbles commonly sold in units of 12, a dozen
Know the units or each substance prepare a table.
Sl No. Substance Units Symbol Remarks
1 Sugar Grams G Lucid Solid
2 Kerosene Oil Litre L Liquid
3 Oxygen Litre L gas
The Unit of Mole
Chemists use the unit of a mole to group atoms, molecules, or other
things into workable units.
Avogadro
If you have a mole of something, that means that you have
602,204,500,000,000,000,000,000 of it.
Amedeo Avogadro
Lorenzo Romano Amedeo Carlo Avogadro,
(/ˌɑːvəˈɡɑːdroʊ/)
Count of Quaregna and Cerreto (9 August 1776 – 9 July 1856), was an Italian scientist, most noted for his contribution to molecular
theory now known as Avogadro's law
Avogadro’s Law states that equal volumes of gases under the same conditions of temperature
and pressure will contain equal numbers of molecules. In tribute to him, the number of
elementary entities (atoms, molecules, ions or other particles) in 1 mole of a substance,
6.022140857(74)×1023, is known as the Avogadro constant, one of the seven SI base units and
represented by NA.
Avogadro
• Born 9 August 1776• Turin, Piedmont-Sardinia• Died 9 July 1856 (aged 79)• Turin, Piedmont-Sardinia• Nationality Italian• Fields Physics• Institutions University of Turin• Known for Avogadro's law
Avogadro constantAvogadro's number
Signature
Avogadro’s Number
Avogadro’s Number
The Avogadro constant 6.022 1023
is defined as the number of atoms in exactly 12 g of carbon-12
Carbon 12
Carbon-12 is the more abundant of the two stable isotopes of carbon, amounting to 98.93% of the element carbon; its abundance is due to the triple-alpha process by which it is created in stars. Carbon-12 is of particular importance in its use as the standard from which atomic masses of all nuclides are measured: its mass number is 12 by definition and contains 6 protons, 6 neutrons and 6 electrons.
Isotope
Any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in the nucleus, or different atomic weights. There are 275 isotopes of the 81 stable elements, in addition to over 800 radioactive isotopes, and every element has known isotopic forms. Isotopes of a single element possess almost identical properties.
Isotopes of Carbon
• Carbon (6C) has 15 known isotopes, from 8C to 22C, of which 12C and 13C are stable. The longest-lived radioisotope is 14C, with a half-life of 5,700 years. This is also the only carbon radioisotope found in nature—trace quantities are formed cosmogenicallyby the reaction 14N + 1n → 14C + 1H. The most stable artificial radioisotope is 11C, which has a half-life of 20.334 minutes. All other radioisotopes have half-lives under 20 seconds, most less than 200 milliseconds. The least stable isotope is 8C, with a half-life of 2.0 x 10−21 s.
Boyle’s Law
Boyle's Law states that Volume of a given mass of dry gas is inversely proportional to its pressure at a constant temperature
Charles's Law
Charlse's Law is Volume of a given mass of a dry gas is directly proportional to its absolute (kelvin) temperature, if the
pressure is kept constant
Guy-Lussac's Law of combining Volumes
Guy-Lussac's Law of combining Volumes states that when gases react, they do so in volumes which bear a simple ratio to one
another, and to the volume of gaseous product, provided that all the volumes are
measured at the same temperature and pressure.
Chemical Element
A chemical element or element is a species of atoms having the same number of protons in their atomic nuclei (i.e. the same atomic number, or Z). There are 118 elements that have been identified, of which the first 94 occur naturally on Earth with the remaining 24 being synthetic elements. There
are 80 elements that have at least one stable isotope and 38 that have exclusively radioactive
isotopes, which decay over time into other elements. Iron is the most abundant element (by mass) making up Earth, while oxygen is the most
common element in the Earth's crust.
Atom
An atom is the smallest constituent unit of ordinary matter that has the properties of a
chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized
atoms. Atoms are very small; typical sizes are around 100 picometers (a ten-billionth of a
meter, in the short scale).
Molecule
A molecule is an electrically neutral group of two or more atoms held together by
chemical bonds. Molecules are distinguished from ions by their lack of
electrical charge
Lot more to it
We’ll discuss it all in our next sessions
