Question

learning: molecules and compounds calculations
question ⓘ
the empirical formula is a chemical formula that provides the smallest, whole-number ratio of elements in a compound. using the mass of each element or the mass percentage of each element in a compound, the empirical formula can be determined.
what is the empirical formula for a substance that contains 21.95% sulfur and 78.05% fluorine by mass?
answer
○ sf
○ sf₄
○ sf₆
○ s₂f₃
○ i dont know yet

Explanation:

Step1: Assume 100g sample, get masses

Mass of S = 21.95 g, Mass of F = 78.05 g

Step2: Calculate moles of each element

Molar mass of S = 32.07 g/mol, Molar mass of F = 19.00 g/mol
Moles of S: $\frac{21.95}{32.07} \approx 0.684$ mol
Moles of F: $\frac{78.05}{19.00} \approx 4.108$ mol

Step3: Find mole ratio (divide by smallest)

Ratio of S: $\frac{0.684}{0.684} = 1$
Ratio of F: $\frac{4.108}{0.684} \approx 6$

Answer:

SF₆