Understanding Ionic and Covalent Compounds

The video tutorial explains the properties of ionic and covalent compounds, focusing on their ability to conduct electricity, their melting points, and their solubility in different solvents. Ionic compounds, composed of positive and negative ions, can conduct electricity in liquid form due to free-moving ions. They have high melting points due to strong ionic bonds. Covalent compounds, made of neutral molecules, do not conduct electricity and have lower melting points due to weak intermolecular forces. Solubility varies: ionic compounds dissolve in water but not in organic solvents, while covalent compounds dissolve in organic solvents but not in water.

What happens to the ions in lead(II) bromide when it is heated to a liquid state?

• They become neutral.

• They move freely.

• They become fixed in place.

• They form a gas.

Why can't covalent compounds like naphthalene conduct electricity?

• They have strong ionic bonds.

• They lack charged particles.

• They dissolve in water.

• They have free ions.

What is a characteristic of the crystal lattice in ionic compounds?

• Weak intermolecular forces.

• No definite structure.

• Low melting points.

• Strong forces between ions.

Why do ionic compounds generally have high melting points?

• Because of strong forces between ions.

• Due to their gaseous state.

• Because they are soluble in water.

• Due to weak forces between molecules.

What is the melting point of naphthalene?

• 80 degrees Celsius.

• 100 degrees Celsius.

• 800 degrees Celsius.

• 200 degrees Celsius.

What is the main reason covalent compounds have low melting points?

• Weak intermolecular forces.

• Strong ionic bonds.

• High solubility in water.

• Presence of free ions.

What allows ionic compounds to dissolve in water?

• Water molecules become charged.

• Water molecules form a gas.

• Water molecules separate the ions.

• Water molecules remain unchanged.

Why is sodium chloride not soluble in ethanol?

• Ethanol molecules become charged.

• Ethanol molecules form a gas.

• Ethanol molecules cannot separate the ions.

• Ethanol molecules separate the ions.

What is a general property of covalent compounds regarding solubility?

• Soluble in water.

• Insoluble in organic solvents.

• Soluble in organic solvents.

• Insoluble in all solvents.

How do organic solvents dissolve covalent compounds?

• By forming a solid.

• By charging the molecules.

• By separating the molecules.

• By forming a gas.