is mole conceept is in the slyaabus of class 10th
Answers
Answer:
mole (symbol mol) is defined as the amount of substance that contains as many atoms, molecules, ions, electrons or any other elementary entities as there are carbon atoms in exactly 12 gm of . The number of atoms in 12 gm of is called Avogadro's number .
The mole is the unit of measurement in the International System of Units (SI) for an amount of substance. The number of molecules per mole is known as Avogadro's constant and is defined such that the mass of one mole of a substance, expressed in grammes, is equal to the mean relative molecular mass of the substance.
Example:
1 mole of hydrogen atoms represents 6.022 × 1023 hydrogen atoms.
1 mole of hydrogen molecules represents 6.022 × 1023 hydrogen molecules.
1 mole of water molecules represents 6.022 × 1023 water molecules.
Mole
Mole is the amount of substance, which contains as many elementary entities as there are in 12 gram of carbon. Elementary entities may be atoms, molecules, ions, electrons or protons.
1mole of a substance always contains the same number of entities irrespective of the identity and kind of the substance.
One mole = molecular mass in grams (molar mass) = 6⋅023×1023 particles = 22.4 litres
Atomicity
Atomicity is the total number of atoms present in one molecule of an element or a substance.
Example:
There are 2 atoms of hydrogen present in H2 molecule. So its atomicity is 2.
The gases can be
Monatomic, example: Helium (He)
Diatomic, example: hydrogen (H2), chlorine (Cl2), oxygen (O2), nitrogen (N2)
Triatomic, example: ozone (O3)
Polyatomic, example: Sulphur (S8).
Molecules may be homoatomic (atoms of same element) or heteroatomic (atoms from different elements e.g. CO2,NH3)
Relative atomic mass(RAM)
Relative atomic mass is a dimensionless physical quantity. In its modern definition, it is the ratio of the average mass of atoms of an element in a given sample to one unified atomic mass unit.
It is expressed in amu.
1 amu = 112ththe mass of a C – 12 carbon atom.
In the case of isotopes, the relative atomic mass is the weighted average of the relative atomic masses of its natural isotopes
Relative molecular mass(RMM)
The molecular mass or molecular weight is the mass of a molecule. It is calculated as the sum of the atomic mass of each constituent atom multiplied by the number of atoms of that element in the molecular formula.
It is the ratio of the mass of one molecule of the compound and the mass of 112th the mass of a C-12 carbon atom.
The most common mistake is to use atomic/proton numbers instead of atomic masses, but remember, except for hydrogen, they are different!
Calculate the RMM of the compound sulphuric acid H2SO4
Relative atomic masses are H = 1, S = 32 and O = 16
RMM = (1 × 2) + 32 + (4 × 16) = 98 (molecular mass of sulphuric acid)
Gram atomic mass
Gram atomic mass is the mass, in grams, of one mole of atoms in a monatomic chemical element. It is numerically equal to the relative atomic mass in grams. The atomic mass of an element expressed in grams is called gram atomic mass.
Example:
oxygen is 16 grams.
1 gram atom of sodium is equal to 23g of sodium.
Gram molecular mass
The molecular mass expressed in grams is called molecular mass or MOLE