Water Project Lab Experiment

Water Experiment Report

Purpose

The purpose of this lab according to my group was to find out which water among the samples that we collected would be most appropriate for freshwater fish to live in as well as which water would be best for salt water fish. To accomplish this, we will use complexometric titration techniques, conductivity and flame tests to determine the presence or lack thereof of certain metal ions that are favorable in saltwater and freshwater respectively.

Procedure

The water samples that were collected were Hill tap water, Leidy Lab tap water, Toilet water and water from the Biopond.

This lab began with preparation for the titration part of the experiment. Only the Toilet water, Biopond water and Hill tap water were titrated. 20mL of each water sample was measured out in a beaker and mixed with 10mL of pH buffer. For the Biopond and toilet water, 7 drops of indicator were mixed into the solution. For the Hill tap water, 4 drops of indicator were added; 5 more drops were added later. Although the desired red color was not achieved, it was deemed acceptable to continue.

It was calculated that .931g EDTA was needed for the titration and .930g was measured out. This was using the original value thought to be the molar mass of EDTA, 372.24g/mole. The EDTA was mixed with 100mL of the water sample being tested in a large beaker on a stir plate. The plan was to, once the EDTA was dissolved, pour it into a 250mL volumetric flask and then fill the flask to the 250mL reading mark with water so as to assure that exactly 250mL of EDTA solution was prepared. The EDTA was left to dissolve as we moved on to the next parts of the lab.

To determine the conductivity of our water samples, the conductivity probe was connected to a computer with LoggerPro and placed in the Sodium Hydroxide standard provided with the kit. It was observed that the probe registered an inaccurate ppm measurement as described on the labeling of the standard. Therefore, the...