I have the mass of one element and the moles of a compound, How do I find the mass of it'd Product? [Zn + 2HCl = ZnCl2 + H2] (Slove for mass of ZnCl2)

3 answers

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Zinc - .5 grams
HCl- .2 moles

Find the Mass of ZnCl2
This is a limiting reagent (LR) problem. You know that because amounts are given for BOTH reactants.

mols Zn = grams/atomic mass = ?
mols HCl = 0.2

Using the coefficients in the balanced equation, convert mols Zn to mols ZnCl2.
Do the same and convert mols HCl to mols ZnCl2
It is likely that the two values for mols ZnCl2 will not agree which means one of them is not correct; the correct value in LR problems is ALWAYS the smaller value and the reagent responsible for that is the LR.
Using the smaller value, convert mols ZnCl2 to grams ZnCl2 by g = mols ZnCl2 x molar mass ZnCl2 = ?