Question d3749

Feb 2, 2015

The density of a gas depends on its mass and its volum (of course), which means that it depends on pressure and temperature.

When you are at STP, 1 mole of any ideal gas occupies exactly $\text{22.4 L}$. SInce no other information is given, you can safely assume that you are dealing with 1 mole of sulfur trioxide ($S {O}_{3}$).

Now, if you have 1 mole, we've established that you have a volume of $\text{22.4 L}$ at STP. All you need now is its mass - for this use $S {O}_{3}$'s molar mass - $\text{80.1 g/mol}$.

This tells you that 1 mole of sulfur trioxide weighs $\text{80.1 g}$.

Therefore, the density of sulfur trioxide at STP is

rho = m/V = ("80.1 g")/("22.4 L") = "3.58 g/L"#

This is a rather lengthy tutorial, but very good, it does not have the sulfur dioxide per se: http://www.eiu.edu/eiuchem/genchem/tutorial6.pdf