VOLTAIC CELL MEASUREMENTS

Wear your safety goggles at all times during this experiment. The solutions used for this experiment can irritate skin and damage clothing. If spilled, wash the area immediately with copious amounts of water. All waste solutions must be placed in the waste containers in the hood. You will work in pairs on this experiment.

Before you come to lab: be sure to complete the advance study assignment for this experiment and attach it to the lab report for the previous week's experiment. Also, be sure to properly prepare your lab notebook. Observation intensive experiments like this one go a lot faster if you have prepared tables or spaces to fill in the results. NOTE: We have not covered electrochemistry yet in lecture; we will begin during the lab week. It is especially important that you prelab using both the lab manual and reading ahead to Chapter 19 in the Lecture text.

Note also that you are asked to decide which electrode systems to study. Attempt to do this before you come to lab. The teaching assistants can provide assistance, but will not do so unless you have tried first. The Teaching Assistants have been instructed to help, but will not do all the work for you. Do not take any more reagent than in necessary to complete the experiment.

During the lab: Reagents will be placed in the hoods or on the side benches. Ask your TA for help if you have any difficulties. Special equipment for building the voltaic cells will be placed on the side benches. The teaching assistant will demonstrate assembly of the voltaic cells. Be sure to follow this carefully. We will not use the design shown in the lab manual. See figure 19.3 in your lecture text for a diagram of the cell we will construct. You will be provided with electrodes of copper, silver, zinc and platinum and a solution of iron for completing your voltaic cells. In the first part of the experiment, there is no need to construct the cells involving the halogen electrodes.

At the end of the experiment: Be sure that all glassware is clean and dry. Be sure that all voltaic cell components are returned to the side bench. You will not be permitted to leave the laboratory until the Teaching Assistant has checked to be sure that all of the electrodes have been returned. Be sure that your lab station is clean and dry. Dispose of waste solutions in the waste containers. Do not pour waste solutions from this experiment down the sink.

Before you leave the lab: perform the calculations for the experiment. Check them with the TA and discuss them. Have your notebook approved by the TA. Remember that the end of lab period is often the easiest/best time to find your TA and get help.

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(nhs) 3/26/97