Law of Constant Composition

Suppose that your instructor gives you two samples and claims that they are both calcium sulfide (CaS). Through a series of tricky chemical reactions, your instructor has you decompose both samples into the constituent calcium and sulfur, and you weigh each of your sample components on the analytical balance. You find that one sample produced 6.30 g Cs and 2.54 g S, while the other produced 3.40 g Ca and 1.90 g S. Are these results consistent with the law of constant composition (see Chapter 5)?

Sample 1: 6.3 g Ca/2.54 g S = 2.5
Sample 2: 3.4 g Ca/1.90 g S = 1.8

No, the results of the ratio between the two samples is different, therefore they are not consistent with the law of constant composition.