Peter performed an experiment to test which of the three compounds his teacher gave him was an ionic compound. The table shows his results.

Question

An 8-column table with three rows. The first row labeled compound has entries A, B, C. The second column labeled hard has entries no, yes, yes. The third column labeled brittle has entries no, yes, yes. The fourth column labeled forms crystals has entries no, yes, yes. The fifth column labeled dissolves in water has entries no, yes, yes. The sixth column has entries labeled boiling point (degrees C) with entries 2567, 1465, and not observed. The seventh column labeled melting point (degrees C) has entries 1083, 801, 180. The eight column labeled conducts electricity has entries labeled no, yes, no.
Which compound (A, B, or C) is most likely an ionic compound?

Answer 1

To determine which compound is most likely ionic based on Peter's experiment results, we can analyze the properties of each compound in terms of the characteristics typically associated with ionic compounds.

1. Hardness: Ionic compounds are generally hard. From the data:

   • Compound A: No
   • Compound B: Yes
   • Compound C: Yes

2. Brittleness: Ionic compounds are usually brittle (they break under pressure):

   • Compound A: No
   • Compound B: Yes
   • Compound C: Yes

3. Forms Crystals: Ionic compounds often form crystalline structures:

   • Compound A: No
   • Compound B: Yes
   • Compound C: Yes

4. Dissolves in Water: Many ionic compounds are soluble in water:

   • Compound A: No
   • Compound B: Yes
   • Compound C: Yes

5. Boiling Point: Ionic compounds typically have high boiling points:

   • Compound A: 2567°C
   • Compound B: 1465°C
   • Compound C: Not observed (not sufficient data)

6. Melting Point: Ionic compounds generally have high melting points:

   • Compound A: 1083°C
   • Compound B: 801°C
   • Compound C: 180°C (low melting point)

7. Conducts Electricity: Ionic compounds conduct electricity when dissolved in water or molten:

   • Compound A: No
   • Compound B: Yes
   • Compound C: No

Conclusion: Based on the properties:

• Compound A does not exhibit characteristics of an ionic compound.
• Compound B shows that it is hard, brittle, forms crystals, dissolves in water, has a high boiling point and a relatively high melting point, and conducts electricity.
• Compound C does not have the typical high melting and boiling points associated with ionic compounds and has low conductivity.

Therefore, Compound B is most likely the ionic compound as it aligns best with all the defining characteristics of ionic compounds.