10.5g of zinc was heated to a constant mass and the residue treated with excess Hcl: ZnCo3+Hcl-----ZnCl2+Co2+H2O.
Calculate the mass of zinc chloride that would be obtained
10.5 g Zn heated to constant mass may form ZnO but not ZnCO3.
To calculate the mass of zinc chloride (ZnCl2) that would be obtained, we need to use the concept of stoichiometry. This involves understanding the balanced chemical equation and the mole ratios between the reactants and products.
First, we need to determine the number of moles of zinc (Zn) that reacted. To do this, we divide the given mass of zinc (10.5g) by its molar mass. The molar mass of zinc (Zn) is 65.38 g/mol.
Number of moles of Zn = Mass of Zn / Molar mass of Zn
= 10.5g / 65.38 g/mol
≈ 0.1604 mol
Next, we need to determine the mole ratio between ZnCl2 and Zn in the balanced chemical equation. From the equation, we can see that the ratio is 1:1. This means that for every 1 mole of Zn, we will obtain 1 mole of ZnCl2.
Finally, we can calculate the mass of ZnCl2 formed by multiplying the number of moles of Zn by the molar mass of ZnCl2. The molar mass of ZnCl2 is 136.29 g/mol.
Mass of ZnCl2 = Number of moles of Zn × Molar mass of ZnCl2
= 0.1604 mol x 136.29 g/mol
≈ 21.88 g
Therefore, the mass of zinc chloride (ZnCl2) that would be obtained is approximately 21.88 grams.