There are two different compounds of sulfur and fluorine. in sf6, the mass of fluorine per gram of sulfur is 3.55 g f/g s. in the other compound, sfx, the mass of fluorine per gram of sulfur is 1.18 g f/g s. what is the value of x for the second compound

For the answer to the question above, 1.18 x 3 = 3.55.
First, you need to find the ratio of F to F in each compound. It is the law of multiple proportions stating that the masses of one element which combine with a fixed mass of the second element are in a ratio of whole numbers. In this case, F would be the "one element" and S would be the "fixed mass", the ratio of F6 to Fx = 3:1 
therefore x would be 2 since there is less F in SFx and the ratio is 3:1. divide 6 by 3 and you get 2.

The correct name for n3-ion should be azide.

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