Methane and ethane are both made up of carbon and hydrogen. in methane, there are 12.0 g of carbon for every 4.00 g of hydrogen, a ratio of 3: 1 by mass. in ethane, there are 24.0 g of carbon for every 6.00 g of hydrogen, a ratio of 4: 1 by mass. this is an illustration of the law of

The answer is: Law of multiple proportions        

Explanation:

The law of multiple proportions is a law of chemical combination given by Dalton in 1803.

According to this law, if more than one chemical compound is formed by combining two elements, then the mass of an element that combines with the fixed mass of other element is represented in the form of small whole number ratio.

Therefore, is an illustration of the law of the law of multiple proportions.