Determinacion De Hierro En Un Mineral

Name of practice:
" Dicromatometría: Preparation and standardization of a solution of potassium dichromate, determination of iron in a mineral." | Number of Practice:4 | Name of student: |

Targetpractice:
* The student will learn to prepare a solution of potassium dichromate and value their concentration using metallic iron by redox titration method dicromatométrica.
* Introducestudents to chemical analysis of ores and alloys, studying the fundamental principles, chemical reactions and interference.
* Give the students the theoretical and practical skills for thedetermination of elements in minerals by a volumetric method.
* By dicromatometría, students determine the concentration of iron in a mineral.
Experimental development:
a) Preparation and evaluation ofa solution of potassium dichromate to determine the stoichiometric factor in the degree of iron.
* Weigh 4 g of potassium dichromate dissolved in distilled water and then dilute to 1000 ml.
*Although from 0.1 to 0.15 g of metallic iron of known purity, placed in a 400 mL beaker and dissolved by adding 20 mL of concentrated hydrochloric acid, heating until complete dissolution.
* Coolslightly and dilute the solution by adding distilled water to a volume of 200 mL To cool you can use a cold water bath.
* Add about 5 g of metallic lead shot, for a total reduction of iron, heatedto boiling and allow 5 minutes.
* Let solution and decant, collecting the solution in another vessel of 400 mL Wash the residue of lead (grit) 2 times with 15 mL portions of hot distilled water,collecting the washings with the decanted solution.
* Cool the solution; add 15 mL of the mixture of sulfuric acid and phosphoric acid. [1] Add a few drops of diphenylamine indicator solution. [2]* Titrate with the potassium dichromate solution to a permanent purple veer.

b) Analysis of a mineral containing iron
* Weigh 1 gram of sample finely pulverized, put into a beaker of...