Experiment 1 Determination of the Acetic Acid Content of Vinegar.
During this experiment you will gain experience in working with volumetric glassware, and gain knowledge on how to determine the uncertainties in the volumes delivered by these. In addition, you will use a suitable titration to determine the concentration of acetic (ethanoic) acid in vinegar samples.
On completion of the laboratory you should be able to:
Demonstrate proper techniques for using `pipette, burette and volumetric flask.
Assess the random error in the volume delivered from the pipette and a burette.
Accurately dilute a sample.
Use a suitable titration to determine the concentration ...view middle of the document...
In this experiment you will start to consider random errors by assessing their magnitudes in the volumes delivered by the pipette, volumetric flask and burette that you use in a titration of an acid (acetic acid) of unknown concentration in vinegar with a base (sodium hydroxide) of know concentration. In subsequent weeks you will calculate the random errors in the determined concentrations.
From the volumes of the acid (pipette) and the base (burette) used and knowledge of the stoichiometry of the reaction that takes place and the concentration of the base, the moles of acid involved in the reaction can be calculated and from that the concentration of acetic acid in the vinegar.
During this experiment you will be working with a weak acid and strong base. You must wear eye protection at all times. In the event that any reagent used in this investigation comes in contact with your skin or eyes, wash the affected area immediately with lots of water. Notify your instructor.
Directly record all observations onto your worksheet.
Carefully pipette, using a pipette filler and a cleaned pipette and the procedures demonstrated to you, 5.00 cm3 of vinegar into a 100 cm3 volumetric flask. Be sure to drain your pipette properly (slowly rotate the pipette while it is draining and discharge the final drop by touching the pipette tip to the side of your titration flask; do not blow out the last drop). Add distilled water up to the bottom of the stem of the flask, mix well and then make up to the 100.00 cm3 mark. To ensure the solution is homogeneous mix thoroughly by slowly inverting the flask at least ten times. Pipette 10.00 cm3 of this diluted vinegar into a...