Does Distilled Water Behave The Same Way?

Physics Project Paper
Name
Institution
Introduction
swimmers are frequently advised to leave the water after strikes of lightening. What is the scientific basis for this? What property of water makes swimmers corned when electricity is around? What other liquids possess the same property? Does distilled water behave the same?
Consider the following;
a. What takes place when a solute dissolves in a solvent? How would this be determined?
b. What process in the molecular level takes place to explain what is observed?
c. Do all solutes dissolve in the same way? Do acids and bases dissolve in the same way?
Solutions capable of conducting electricity, such as ionic compounds, are referred to as electrolytes. There are three major classifications
of electrolytes; salts, acids, and bases. Non-electrolytes do not conduct electricity (Schwarz, 2006).
A notable property of electrolytes is that they dissolve in water, and partially dissociate into free ions.
Strong electrolytes disassociate completely, while weaker electrolytes only disassociate partially.
Electrolytes
Acids
Acids dissociate (or ionize) in water and produce hydronium ions. Strong acids dissociate completely while weaker acids ionize to a lesser degree.
Bases
Bases dissociate in water to produce hydroxide ions. Like in the case of acids, strong bases ionize completely, while weak bases only ionize partially.
Salts
Salts are different from acids and bases. They dissociate in aqueous solutions to produce a negative non-metal ion, and a positive metal ion. Soluble salts like the common table salt (NaCl) dissociates almost completely in aqueous solutions, while less soluble salts only disassociate partially (Schwarz, 2006).
Non-electrolytes
Some common non-electrolytes are table sugar (C12H22O11), and ethanol (CH3CH2OH).
Simple circuits can be constructed in the lab to test the conductivity of various solutions. The conductivity of these solutions can be determined using both qualitative and quantitative techniques. The conductivity of a solution is dependent on;
• Type of solute,
• Concentration of the solution, and
• The movement of ions in the
solution.
In the test, the number of free ions can be determined by the brightness of the bulb; and also represents the amount of current flowing through the solution. The brightness of the bulb is a qualitative measure. The quantitative measure in the same test would be the conductive value in Siemens/cm.
In the lab, I will construct an inexpensive conductivity experiment using a nine volt battery and a light emitting diode.
Purpose of experiment
In this experiment, I will put up a conductivity test aimed at studying the electrical conductivity of water and other water solutions. The solutions will be categorized as either electrolytes or non-electrolytes, and their conductivity variations noted. The experiment will utilize readily available materials;
• hydrochloric acid (stomach acid), HCl
• Acetic acid (vinegar) CH3COOH
• Sodium hydroxide (common in soaps and detergent) NaOH
• Ammonia (household cleaner) NH3
• Calcium hydroxide (slaked lime) Ca(OH)2
• Sodium chloride (common table salt) NaCl
• Ethanol (found in alcoholic drinks, and gasoline) CH3CH2OH
• Sucrose (table sugar) C12H22O11
Materials;
• 30 mL distilled water
• 30 mL tap water
• 30 mL 1.0 mol/L HCl in a 100 mL beaker
• 30 mL 1.0 mol/L CH3COOH in a 100 mL beaker
• 30 mL 1.0 mol/L NaOH in a 100 mL beaker
• 30 mL 1.0 mol/L NH3(aq) in a 100 mL beaker
• 30 mL 1.0 mol/L Ca(OH)2 in a 100 mL beaker
• 30 mL 1.0 mol/L NaCl in a 100 mL beaker
• 30 mL 1.0 mol/L CH3CH2OH in a 100 mL beaker
• 30 mL 1.0 mol/L C12H22O11 in a 100 mL beaker
• Microplate
• 15 Eyedroppers
• Wash bottle with distilled water
• Conductivity tester
Procedure
The first step is to make a conductivity tester as explained below;
Making the conductivity tester
Requirement

• 1 light emitting diode (LED)

• 1 KOhm resistor
• 1 piece of fiber board
• 1 rubber band
• 1 9 Volt battery
• 1 battery connector
• 3 pieces of wire
• Tape To test the conductivity of the different solutions, I immerse the open wire ends in each; to complete the circuit.
The conductivity of each is represented by the brightness of the light. Brighter light indicates more conductive solution while less conductive solutions only produce dim light.
This table is used to clearly establish the conductivity of the different solutions; 0 for non-conductor- to 4 for excellent conductor.
Scale of Conductivity
Scale LED Brightness Conductivity
0 Off Very low or none
1 Dim Low
2 Medium Medium
3 Bright
High
4 Very Bright Very High

For accurate results;
• Dim the laboratory lights
• Use a clean, dry microplate
Results
Make records of the intensity of the light from the LED for each of the solution. The brightness of the bulb should be denoted under five categories; off, dim, medium, bright, very bright. These readings should correspond to conductivity records of; none, low, medium, high, very high.
Solution Tested Bulb Brightness Conductivity
Distilled Water Off Very low or none
Tap Water Off Very low or none
HCl, 1 mol/L Very Bright Very high
CH3COOH, 1 mol/L Dim Low
NaOH, 1 mol/L Very Bright Very High
NaCl, 1 mol/L Bright High
NH3(aq), 1 mol/L Dim Low
Ca(OH)2, 1 mol/L Dim Low
C12H22O11, 1 mol/L Off Very low or none
CH3CH2OH, 1 mol/L Off Very low or none

Conclusion
In the test, properties of electrolytes (both strong and weak), and non-electrolytes are observed in aqueous solutions. When the tester is dipped into a solution that has free ions, a circuit is completed. This lights up the LED bulb. The brightness of the bulb is determined by the degree of the solution to conduct electricity. Strong electrolytes have more free ions, which results in brighter light. Weaker electrolytes, however, can only free few ions, and only cause the bulb to produce dim light. Non-electrolytes do not result in the conductivity of the aqueous solution, and the light does not glow.
Reference
Schwarz, K. (2006). Materials Design of Solid Electrolytes. Proceedings of the National Academy of Sciences of the United States of America, 103(10), 3497.