I. Introduction
1. What are the two classes of compounds based on the type (metal or non-metal and polyatomic ions) of elements or ions they are made of?
2. How do they behave in solution? Which one exists as ions in solution?
3. What are ions and molecules?
4. What is electrical conductivity of aqueous solutions and why is it considered a physical property?
5. How are soluble substances classified according to their ability to conduct electricity?
6. What are strong, weak and non-electrolytes and their capability to conduct electricity?
7. Why electrical conductance considered an evidence of a chemical reaction?
8. What were the objectives of this experiment?
9. How was conductivity tested in this experiment?
10. What were the chemical and procedural hazards in this experiment and the safety precautions observed to avoid the risk of these hazards?
II. Results Analysis
A. Data and Calculations
Please refer the reader to the attached datasheet.
B. Discussion
Part I Conductivity Testing – Evidence for Ions in Aqueous Solution
1. How was the conductivity test performed? What must be done to the electrode after each conductivity test?
2. What were the conductivity readings of distilled water and tap water? Briefly explain the reason for the difference.
3. What were the conductivity readings of solid NaCl and its solution in water? Briefly explain the reason for the difference.
4. What were the conductivity readings of solid CaCO3 and its solution in water? Briefly explain the reason for the difference.
5. Based on your conductivity light bulb observation, which ones were strong electrolytes and which ones were weak? Briefly support your analysis with the concept you learned in this experiment.
6. What form or type of particles do strong electrolytes, weak electrolytes and non-electrolytes contain?
Part II Reactivity of Aqueous Solutions: Typical Chemical Reactions and Net Ionic Equations
A. Reaction between 0.1 M HC2H3O2 and 0.1 M NH4OH
1. What were the electrical conductivity readings of 0.1M HC2H3O2 and 0.1M NH4OH before and after mixing? What does the difference in conductivity between the reactants and products indicate?
2. What does the net ionic equation of this reaction indicate?
3. What type of reaction had occurred?
B. Reaction Between H2CO3 and Saturated Ba(OH)2 Solutions
1. What was the electrical conductivity of distilled water and after blowing with CO2?
2. What was the electrical conductivity of the 0.1M Ba(OH)2 solution, and as CO2 is bubbled in it using a straw? What does the difference in conductivity between the reactants and products indicate?
3. What does the net ionic equation of this reaction indicate?
4. What type of reaction had occurred? How did you use the solubility rules to determining the reaction type?
5. How do you use the particle type or form to predict the reaction type and products formed?
6. Why is conductivity important in predicting the type of reaction and in writing net ionic equations?
PART III Conductivity of Household/Commercial Products
1. Based on your conductivity light bulb observation, which commercial products were strong electrolytes, weak electrolytes and non-electrolytes? Briefly support your analysis with the concept you learned in this experiment.
2. Why is Gatorade a strong electrolyte, even though the dominant substance is glucose? Briefly explain.
3. What is the practical application of the electrolytic properties of substances in solutions?
III. Conclusions
1. What can one conclude about the electric conductance of aqueous solutions?
2. Based on the results in Part I, what can be inferred from the electrical conductance of
solid compounds, non-electrolytes, weak electrolytes and strong electrolytes?
3. What factors affect the ability of these tested substances to conduct electricity?
4. Based on the results in Part II, what can be inferred from the use of electrical conductance
as evidence of a chemical reaction?
5. How does the conductivity test prove the occurrence of a chemical reaction?
6. What lab techniques were learned in this experiment?
7. Were all the expected results achieved? If not, what was the primary causes of errors?
8. What is the practical application of this experiment? Briefly give one example.
