Carbon is found to form two oxides, which contain 42.9% and 20.0% of carbon. Show that these figures illustrate the law of multiple proportions. find the different weights of carbon combining with fixed weight of oxygen will be

Step 1: To calculate the percentage composition of carbon and oxygen in each of the two oxides  First oxide  Second oxide   Carbon 42.9%20% (Given)  Oxygen 57.1%80% (by difference) Step 2: To calculate the weights of carbon which combine with a flxed weight, i.e., one part by weight of oxygen in each of the two oxides.In the first oxide, 57 .l parts by weight of oxygen combine with carbon : 42.9 parts..'. 1 part by weight of oxygen will combine with carbon 42.957.1=0.751In the second oxide, 80 parts by weight of oxygen combine with carbon : 20 parts..'. I part by weight of oxygen will combine with carbon2080=0.25Step 3: To compare the weights of carbon which combine with the same weight of oxygen in both the oxides. The ratio of the weights of carbon that combine with thesame weight of oxygen (1 part) is 0.75 :0.25 or 3 : 1. Since this is a simple whole number ratio, so the above data illustrate the law of multiple proportions. 3:1=3