Question

How many moles of MgS2O3 are in 175g of the compound

Answer 1

I think this is what you are asking let me show you this equation:
\[175gofMgS_{2}O_{3}*\frac{1moleMgS_{2}O_{3}}{ 136.432gof MgS_{2}O_{3}}=1.28 moles MgS_{2}O_{3}\]

Answer 2

You can probably see how the unit g is being crossed out here to get moles because g/g gets rid of g. you are left with mole.

Answer 3

also for the g of MgS2O3 you need to use a periodic table here:
http://utahchemicalengineering.files.wordpress.com/2008/10/periodic_table_of_elements1.jpg
here is the formula weight equation:
\[24.305+2(32.065)+3(15.999)=136.432\]
there ya go

Answer 4

1.28 moles