Question

What is the Empirical formula of a compound with $40$% sulfur and $60$% oxygen by mass?

• A. $SO$
• B. $S_2{O}_3$
• C. $S_2{O}_7$
• D. $S{O}_3$
• E. $S{O}_2$

Answer 1

The correct option is D $S{O}_3$

The ratio of $S:O=40:60$ by mass.

The molar mass of $S=32$

The number of moles of $S=\frac{40}{32}=1.25$

The molar mass of $O=16$

The number of mole of $O=\frac{60}{16}=3.75$

Molar ratio of $S:O=1.25:3.75=1:3$

The empirical formula would be $=S{O}_3$