chemistry  DrBob222
posted by eddy .
For this question can u please explain steps 3 and 4
4.0 g of ferrous ammonium sulphate, FeS04(NH4)2 SO4 6H20, is used. The oxalate is in excess, calculate the theoretical yield of the iron complex. Can someone please show me how to calculate a question like this please?
Thank you
1. Write the equation and balance it.
2. Convert 4.0 g of the ferrous ammonium sulfate to moles. #moles = grams/molar mass.
3. Using the coefficients in the balanced equation, convert moles of the ferrous ammonium sulfate to moles of the iron complex.
4. Finally, convert moles of the iron complex to grams. # grams = moles x molar mass. The number of grams of the iron complex is the theoretical yield.

Have you the balanced equation? If you have then step 3 is the easy step.
Lets say that the balanced reaction is
2A +3B> 2C +D
this means that 2 moles of A yields 2 moles of C and one mole of D. So if we start with 1 mole of then this will form 1 mole of C and 0.5 mole of D. Or if we start with 0.2 mole of A then we get 0.2 mole of C and 0.1 mole of D.
For part 4. If we get M moles as the answer to part 3 then the mass of complex is
mass = M x molar mass of complex. 
would my final answer be 3.2 g