I have set up the following problem so you will have a chance
to do it before seeing the answers and how the answers are
calculated. Try answering each of the cells in the indicated
order and then check to see if you understand the problem.
In this particular case either the molar mass or the number
of moles of sample can be calculated first. Let's go ahead and do
the molar mass first. Try to determine the correct molar mass of
Cr2O3 before clicking on the link.