. Oleum or fuming sulfuric acid available commercially in concentrations ranging from 20 to 99.9% sulfur trioxide.

A. What is the percent by mass of sulfur trioxide (SO3) if oleum is expressed as 3H2SO4 . 5SO3? Show your solution.

B. Discuss at least three potentially hazardous features associated with concentrated sulfuric acid.

%SO3 = (5*molar mass SO3/3*mols mass 3H2SO4.5H2O)*100 = ?

I will leave part B to you. You can google H2SO4 and find plenty of information about the hazards of H2SO4.