-It is defined as number of parts by weight of that element it is combined or displaced by 1.008 part by weight of hydrogen or 8 parts by weight of oxygen or 35.5 parts by weight of Chlorine.
-In general;
Eq.wtofYEq.wtofX=wt.ofYwt.ofX
i) Eq.wtofelement=valencyAt.wt
ii) Eq.wtofacid=No.ofH+displacedpermoleculeMol.wt=BasicityofacidMol.wt(Basicity=No. of OH−ion reqd. by one molecule of acid for complete neutralization or simply no. of H+ displaced.)
iii) Eq.wtofbase=AcidityofbaseMol.wt(Acidity=No. of H+ combined per molecule per molecule of base)
Atomicity is defined as the total number of atoms present in a molecule. For example, each molecule of oxygen (O2) is composed of two oxygen atoms. Therefore, atomicity of oxygen is 2.
Atomicmass=equivalentmass×valency
Dulong-Petit law:
-Atomicweight×specificheat=6.4 Or, Atomicheat=6.4
-This law is only applicable to solids except Boron, Carbon and Silicon.
Molecular Mass\Weight:
It is the relative weight of substance and is algebraic sum of atomic weight of all atoms present in the molecule.
Expressed in terms of grams is gram molecular weight.
Molecular weight is number of times a molecule of substance is heavier than 121thofC−12 atom.