Question

Physical properties can be a useful way of classifying substances as ionic or covalent (molecular).

Ionic compounds usually have high melting points, are soluble in water and conduct electricity when in solution.
Covalent compounds usually have low melting points and are less soluble in water. When covalent compounds do dissolve in water, they tend to have low conductivity.
Classify each of the five substances (potassium chloride, copper(II) chloride, adipic acid, sucrose, and vanillin) as ‘ionic’ or ‘covalent’ based on your test results.

Answer 1

Answer and Explanation:

Based on the provided information about the physical properties of ionic and covalent compounds, we can classify each substance as either 'ionic' or 'covalent'.

1. Potassium chloride (KCl):

- High melting point: Potassium chloride has a high melting point, indicating an ionic compound.

- Soluble in water: Potassium chloride is soluble in water, further suggesting an ionic compound.

- Conductivity in solution: Potassium chloride can conduct electricity when dissolved in water, consistent with an ionic compound.

Classification: Ionic

2. Copper(II) chloride (CuCl2):

- High melting point: Copper(II) chloride has a high melting point, suggesting an ionic compound.

- Soluble in water: Copper(II) chloride is soluble in water, indicating an ionic compound.

- Conductivity in solution: Copper(II) chloride can conduct electricity when dissolved in water, supporting an ionic compound.

Classification: Ionic

3. Adipic acid (C6H10O4):

- Low melting point: Adipic acid has a low melting point, indicating a covalent compound.

- Soluble in water: Adipic acid is less soluble in water, which aligns with a covalent compound.

- Conductivity in solution: Covalent compounds like adipic acid tend to have low conductivity when dissolved in water.

Classification: Covalent

4. Sucrose (C12H22O11):

- Low melting point: Sucrose has a low melting point, suggesting a covalent compound.

- Soluble in water: Sucrose is soluble in water, but its solubility does not imply ionic character.

- Conductivity in solution: Covalent compounds like sucrose typically have low conductivity in solution.

Classification: Covalent

5. Vanillin (C8H8O3):

- Low melting point: Vanillin has a low melting point, indicating a covalent compound.

- Soluble in water: Vanillin is less soluble in water, aligning with a covalent compound.

- Conductivity in solution: Covalent compounds like vanillin tend to have low conductivity in solution.

Classification: Covalent

In summary, based on the physical properties provided, the classification of each substance is as follows:

- Potassium chloride: Ionic

- Copper(II) chloride: Ionic

- Adipic acid: Covalent

- Sucrose: Covalent

- Vanillin: Covalent