CHM 120 – Spring 2004

Experiment 10:

Gravimetric determination of lead as the chromate

NAME: __________________________________

SECTION: ________________________________

DATE: ___________________________________

PLEDGE: _________________________________

PRELABORATORY EXERCISES

  1. Provide definitions for the following terms:

(a) solubility

 

(b) saturated solution

 

 

(c) solubility product constant

 

 

(d) gravimetric determination

 

 

 

2. What safety precautions will you be taking in carrying out this lab?

 

 

 

3. Give the chemical equation that describes the equilibrium between
  1. lead(II) chromate and its ions in a saturated solution

     

     

  2. lead(II) sulfate and its ions in a saturated solution

 

 

4. In this experiment you are told to wash the precipitate until "free of chromate". Indicate, with the aid of equation(s), how you are going to tell when the precipitate is free of chromate.

 

 

 

 

5. What is the fundamental difference between gravimetric and volumetric analysis?