Biolab 3

Jamie Hamill Lab: Water Conductance Week: # 4

WATER CONDUCTANCE

Introduction

The purpose of this week 4 iLab was to find the unknown concentration of a NaCl solution using a standard curve of conductivity. Because water contains very few ions it does not conduct electricity very well. When NaCl solution is dissolved in water, the solution conducts very well, because the solution contains ions. The ions come from the table salt, whose chemical name is sodium chloride. Sodium chloride contains sodium ions, which have a positive charge, and chloride ions, which have a negative charge. Because sodium chloride is made up of ions, it is called an ionic substance. After completing the experiment and plotting each conductivity value I found that as the NaCl increased in concentration and so did the conductivity

Procedure

There are 4 parts in this iLab experiment.

Part 1: Create Standard Curve

1) select five 250 mL beakers for the equipment tab and label them 1-5
2) Fill each beaker with 100 mL of water
3) Fill each beaker with the appropriate mg of NaCl by following the chart below
4) Stir the solutions
5) Using a conductivity meter in ATC mode measure the conductivity of all the beakers
6) Record results and put on Table 1

Part 2: Determine Conductivity of Unknown Brine Solutions

1) Select three 250 mL beakers from equipment tab and label them 1 - 3
2) Fill beaker 1 with 100mL of unknown brine solution 1
3) Fill beaker 2 with 100mL of unknown brine solution 2
4) Fill beaker 3 with 100mL of unknown brine solution 3
5) Stir the solutions
6) Using a conductivity meter in ATC mode measure conductivity of all beakers
7) Record results on Table 2

Part 3: Make Standard Curve ( Graphing Tools)

1) To graph the results from Part 1 use Excel software
2) Let the X axis represent NaCl Concentration and Let the Y axis represent the Conductivity

Part 4: Determine Concentrations of Unknown NaCl