University:
California State University, Northridge
Course:
CHEM 101 | General Chemistry I
Academic year:

2011
Views:

481

Pages:

2
Author:

Erica Hancock

Solutions for Gravimetric Analysis Questions Check for Understanding 4.1 1. Determine the solubility of AgCl using Ksp for AgCl and a table of initial and equilibrium concentration terms. AgCl(s) X Ag+(aq) + Cl-(aq) init equil 0.0060 0 0.0060 + x x where x = increase in [Cl-] = solubility of AgCl at equil, Ksp = 1.8 x 10-10 = [Ag+][Cl-] = (0.0060 + x)(x) • 0.0060x Y x = 3.00 x 10-8 M 2. Check for Understanding 4.2 1. Often the solubility of a slightly soluble salt is increased in acidic solution because the anion combines with H+ to form a weak acid. Removal of the anion shifts the equilibrium toward more dissolution of the salt. Since Cl- would form a strong acid (HCl) that is ~100% ionized in solution, it is not removed from solution. Therefore, AgCl is not more soluble in acidic solution and the presence of HNO3 does not increase its solubility. Check for Understanding 4.3 1. First, determine the solubility of AgCl using Ksp for AgCl and a table of initial and equilibrium concentration terms. AgCl(s) X Ag+(aq) + Cl-(aq) init 0 0 equil x x Solutions for Gravimetric Analysis Questions at equil, Ksp = 1.8 x 10-10 = [Ag+][Cl-] = (x)(x) Y x = 1.34 x 10-5 M In order to estimate the error that this precipitate mass loss involves, one must know the total mass of the AgCl precipitate. This can be calculated from the original unknown sample mass and the mass percent chloride in the unknown. Assuming a sample size of 0.25 g that is 50% Cl- by mass,

Solutions for Gravimetric Analysis Questions

of 2

Description

Free up your schedule!

Take 5 seconds to unlock