5 g of clacium reacts with 2 g of oxygen to form a compound. Find the molecular formula of the compound.(Atomic mass of Ca= 40 u, O=16u
= (5 / 40) = 0.125
= (2 / 16) = 0.125
Now calculate the simplest ratio of the element. For this we will divide the number of moles of each element by the smallest value. But as the number of moles of each element is 0.125, therefore calcium and oxygen are present in a ratio of 1 : 1. Thus the empirical formula of the compound is CaO.