Answer to Question #153760 in General Chemistry for Morayo

Question

10.5g of zinc trioxocarbonate(IV) were heated very strongly to a constant mass and the residue treated with excess Hcl. Calculate the mass of zinc chloride that would be obtained(Zn=65, C=12, O=16, H=1, Cl= 35.5)

Answer 1

ZnCO₃==> ZnO + CO₂

ZnO + 2HCl ==> ZnCl₂+ H₂O

mols ZnCO₃ = grams/molar mass = ?

1 mol ZnCO₃ gives 1 mol ZnO

1 mol ZnO produces 1 mol ZnCl₂.

grams ZnCl₂ = mols ZnCl₂ x molar mass ZnCl₃.

ZnCO₃+2HCl ==> ZnCl₂+ H₂O+CO₂

1 mole of ZnCO₃=1 mole of ZnCl₂

1 mole =(10.5/125)

Therefore, (10.5/125 )×136

Mole=mass/molar mass

Mass = molar mass × mole

i.e. m =136 × 0.1

m = 13.6g