Mass of strontium iodide contained in a 350 mL solution What mass (in mg) of strontium iodide is contained in $350\ \mathrm{mL}$ of a strontium iodide solution that has a concentration of $1.93\ \mathrm{µM}$?


What I have done: 

$0.350\ \mathrm{L}\ \ce{SrI_2}\cdot \frac{1.93\cdot 10^{-6}}{1\ \mathrm{L\ Solution}}\cdot \frac{341.42\ \mathrm{g}\ \ce{SrI2}}{1\ \mathrm{mol}\ \ce{SrI2}}=2.31\cdot 10^{-4}~\mathrm{g}~\ce{SrI2}=0.231~\mathrm{mg}~\ce{SrI2}$

What is not correct here?
The mistake is that you didn't write "mol" after $1.93 \times 10^{-6}$.

Some teachers/professors might let that go, others wouldn't, depending upon what they are really trying to teach you.

Units and dimensional analysis are important.