Substance

Question

Bond Type
Dissolves in Water
(Yes or No)
Conducting Ability of Dry Substance
(Strong, Weak or None)
Conducting Ability
of Wet Substance/ Solution (Strong, Weak or None)

NaCl
ionic
yes
x
STRONG

MgSO4
ionic
yes
x
STRONG

Vanillin C8H8O3
covalent
no
x
does not conduct electricity

Stearic acid
covalent
no
x
WEAK conductor

Fe
metallic bonds.

NO
Yes strong----
None

Zn
metallic
NO
Weak
None

Draw a model of an ionic solution using one of the tested compounds. (12 points)

Write a conclusion using the CER model and data evidence from the data table to answer the essential question. (20 points)

Answer 1

Model of an Ionic Solution (NaCl or MgSO4)

Since I cannot draw, I will describe how you would visualize the model of an ionic solution using sodium chloride (NaCl) as an example:

1. Dissociation in Water: In the model, represent water molecules with a "V" shape, where the oxygen atom (larger circle) is at the tip and the two hydrogen atoms (smaller circles) are on either side. These molecules will be drawn around the ions to show the interaction with water.

2. NaCl Representation: For sodium chloride, draw a sodium ion (Na⁺) as a small blue circle and a chloride ion (Cl⁻) as a small green circle.

3. Ionic Interaction: Place several water molecules around the Na⁺ and Cl⁻ ions to illustrate how they dissociate in water. The negative end of the water molecule (the hydrogen end) should be near the Cl⁻ ion, while the positive end (the oxygen end) should be near the Na⁺ ion, representing the attraction between the polar water molecules and the ions.

4. Label: Label each part of the model, including the water molecules, Na⁺ ions, Cl⁻ ions, and any important characteristics like dissociation, ion polarization, and solvation.

Conclusion Using the CER Model

Claim: Ionic compounds, when dissolved in water, conduct electricity due to the presence of dissociated ions.

Evidence: The data from the table indicates that both NaCl and MgSO₄ are ionic substances that dissolve in water and display strong conducting abilities in their wet state. For instance, NaCl dissociates into Na⁺ and Cl⁻ when dissolved, creating a solution that allows for the free movement of charged particles, which is essential for conducting electricity.

Reasoning: The ability of ionic compounds to conduct electricity is linked to their structural properties and behavior in solution. In their solid state, ionic compounds are held together by strong electrostatic forces in a lattice structure, which does not allow for electron mobility. However, when dissolved in water, these compounds dissociate into individual ions. The movement of these free ions in the solution allows electric current to pass through, demonstrating a strong conducting ability in wet solutions, as evidenced by the "Strong" classification in the data table for both NaCl and MgSO₄.

Therefore, the data and reasoning support the claim that the ionic nature of compounds like NaCl and MgSO₄ leads to their ability to conduct electricity when in solution form. The dissociation into free ions is crucial for this conductivity, highlighting the importance of the interaction between ionic substances and polar solvents such as water.