(a) State the various postulates of Dalton’s atomic theory of matter.
(b) Which postulate of Dalton’s atomic theory can explain the law of conservation of mass?
(c) Which postulate of Dalton’s atomic theory can explain the law of constant proportions?
(a) Postulates of Dalton’s atomic theory:
(i) All the matter is made up of very small particles called ‘atoms’.
(ii) Atoms cannot be divided.
(iii) Atoms can neither be created nor be destroyed.
(iv) Atoms are of various kinds. There are as many kinds of atoms as are elements.
(v) All the atoms of a given element are identical in every respect, having the same mass, size and chemical properties.
(vi) Atoms of different elements differ in mass, size and chemical properties.
(vii) The ‘number’ and ‘kind’ of atoms in a given compound is fixed.
(viii) During chemical combination, atoms of different elements combine in small whole numbers to form compounds.
(ix) Atoms of the same elements can combine in more than one ratio to form more than one compound.
(b) The postulate “The elements consists of atoms and that atoms can neither be created nor destroyed” can be used to explain the law of conservation of mass.
(c) The postulate “The elements consist of atoms having fixed mass, and that the number and kind of atoms of each element in a given compound is fixed” can be used to explain the law of constant proportions.