Stoichiometry Lab Report

Stoichiometry of Reactions Jessica Scanlan

Experiment No. 7 CHMY 142-25

10/14/14 Trenton Hopkins

I. Introduction

The purpose of this experiment was to examine how the stoichiometry, “the quantitative relationships between substances involved in a chemical reaction”, can be applied to determine the quantity of sodium hypochlorite found in a bleach product. This experiment allowed it to determine how much oxidizing agent is in a cleaner by using a redox reaction, which is a reaction involving the transfer of electrons from the compound being oxidized to the compound being reduced. To determine the amount of oxidizing agent, it is necessary to accurately measure out known amounts of redox reactants, know the stoichiometry

Record the volume of the sodium thiosulfate solution used in the titration, and repeat the procedure in a duplicate titration.

Using the Volumetric Pipette:

1. Compress the safety bulb, hold it firmly against the end of the pipette. Then release the bulb and allow it to draw the liquid into the pipette.

2. When the liquid level is above the calibration line on the pipette, remove the bulb quickly and put your thumb or index finger over the pipette. Carefully “roll” finger to the side and allow the liquid to drop until the meniscus is level with the mark. Then hold the pipette over the flask to receive the liquid and remove the finger. Allow the liquid to drain out.

Determination of the Oxidizing Capacity of a Household Cleaner:

1. Place a clean, dry 125 mL Erlenmeyer flask on balance, and slowly dispense liquid bleach until there is about .5 g. Record the mass of bleach, and add 25 mL of de-ionized water and about 2 g of KI. Swirl contents until the KI dissolves. Then add 3 drops of 1 M H2SO4, mix, and let stand for 1 or 2 minutes.

2. Then titrate with the sodium thiosulfate solution as in the standardization procedure, adding 6 drops of starch indicator near the end of the titration. Record the volume of thiosulfate solution used in the titration. Make a duplicate