Posted by kate on .
3.00 g of Zn is allow to react with 1.75 g CuSO4 . calculate how many grams of Zn will remain after the reaction is complete ?
This is a limiting reagent (LR) problem in reverse. First you must identify the LR reagent.
Zn + CuSO4 ==> Cu + ZnSO4
mols Zn = grams/atomic mass.
mols CuSO4 = grams/molar mass.
Using the coefficients in the balanced equation, convert mols Zn to mols Cu. Do the same for mols CuSO4. Most likely these two values will not be the same which means one of them is not right; the correct value in LR problems is ALWAYS the smaller value and the reagent producing that value is the LR.
Using the coefficients in the balanced equation, convert mols of the LR to mols of the "other" reagent. Convert mols of the other reagent to grams. g = mols x molar mass and subtract from the initial grams. That will be the amount left over.