Fundamental chemical laws The fundamental chemical laws consist of the Law of conservation of mass , the law of definite proportions, and the law of multiple proportions. The Law of conservation of mass The law of conservation of mass states that mass is neither created nor destroyed. The law of definite proportions The law of definite proportions states that a given compound always contains exactly the same proportion of elements by mass. The law of multiple proportions The law of multiple proportions states that when two elements form a series of compounds, the ratios of the masses of the second element that combine with one gram of the first element can always be reduced to small whole numbers. 
