A chemistry student determined the empirical formula for titanium sulfide (Ti_xS_y). To do so, she reacted titanium with excess sulfur in a crucible, and recorded the following data: $\begin{array}{lr} \text { Weight of crucible } & 11.120 \mathrm{~g} \ \text { Weight of titanium } & 8.820 \mathrm{~g} \ \text { Weight of crucible and product } & 31.700 \mathrm{~g} \end{array}$ What is the empirical formula of titanium sulfide

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Quizplus · Accepted Answer

The student reacted titanium with excess sulfur, so we can assume that all of the titanium reacted and therefore the subscripts for titanium should be 1. Additionally, the student determined the ratio of sulfur atoms to titanium atoms to be 1.2, meaning that there are 1.2 times as many sulfur atoms as there are titanium atoms. However, we cannot have a fraction as a subscript in a chemical formula, so we must multiply both subscripts by a factor that will make them whole numbers. The smallest factor that will do this is 5, which gives us the formula Ti5S6. We can simplify this formula by dividing all subscripts by their greatest common factor, which is 1. This gives us the empirical formula TiS6. However, none of the answer choices match this formula exactly. Choice C is the closest, as it has the same subscripts for Ti and S but includes an unnecessary subscript of 1 for the second S atom. Therefore, choice C is the best answer.

A Chemistry Student Determined the Empirical Formula for Titanium Sulfide