# Oleum - Mass and Hazardous Features

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.

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#### Solution Preview

Hi there,

Consider the following information when formulating your answers.

Part A

To determine the percent by mass of SO3, you will need the molar mass of H2SO4 as well as SO3.

H2SO4 = 98.078 g/mol

SO3 = 80.063 g/mol

Now, we need to factor in the stoichiometric coefficients for each species in oleum to determine the molar mass of oleum.

Molar mass 3H2SO4 . 5SO3 = (98.078 x 3) + (80.063 x 5)

= 694.549 g/mol

The percent by mass of SO3 can then be calculated:

Percent SO3 = [(80.063 x 5) x 100]/694.549

...

#### Solution Summary

A complete worked through solution for the percent by mass composition of this oleum related question is provided. Additionally, four hazardous features of concentrated sulfuric acid are detailed. Includes references.