(a) State the phenomenon illustrated by the:
(i) spreading of the smell of hydrogen sulphide gas in the laboratory;
(ii) existence of atoms of the same element having different mass numbers
(b) The atomic number of an element is 17. It has different atoms containing 18 neutrons and 20 neutrons, with a relative abundance of 75% and 25% respectively. Calculate the relative atomic mass of the element.
Explanation
(i) The spreading of a smell is called diffusion which is simply the movement of parbcies of a substance from region of higher concentration to that of lower concentration.
(ii) Isotopy.
(b) The relative atomic mass = (18 x 0.75) + (20 x 0.25) = 13.5 + 5 = 18.5.