chp 1 : Some basic concepts of chem

Laws of chemical combinations

Law of conservation of mass

Definition :

In all physical and chemical changes the total mass of the reactants is equal to that of the products.

example

Law of constant / definite proportion

Definition :

percentage of element in a compound by mass remains same even if the source of the compound is different

example - in water - H : O, will always be [2:16] even if from rain water or ground water, or from chem reaction.

Isotopes -

Note

example -

Limitation : non - stoichiometric compound do not follow this law.

Law of multiple proportion

Definition :

Example

limitations

Law of reciprocal proportion

Definition :

Example

Gay Lussac’s law of gaseous volume

Definition :

examples - and conditions

conditions - same temperature, pressure. has to be balanced eqn

Atomic mass

Relative atomic mass (RAM)

Definition :

Atomic mass unit (Amu)

Atomic mass / molecular mass

NOTE

example -

Gram atomic mass

Atomicity

The number of atoms in a molecule is called atomicity

example ;

Number of p, e, n in a Molecule

Moles