Question 1: Ionic compounds are formed through the electrostatic attraction between positively charged ions (cations) and negatively charged ions (anions). These compounds typically exhibit high melting and boiling points, are soluble in water, and conduct electricity when molten or dissolved. Understanding these properties helps in recognising ionic compounds in real-world applications.

Answer: Ionic compounds have high melting and boiling points, are soluble in water, and conduct electricity when molten or dissolved.

Question 1: Define an ionic compound.

Answer: An ionic compound is a chemical compound composed of ions held together by electrostatic forces.

Question 2: Explain why ionic compounds conduct electricity when molten or in solution.

Answer: Because ions are free to move and carry charge in the liquid or dissolved state, allowing conduction.

Question 1: Calculate the number of moles in 50 grams of sodium chloride (NaCl). (Molar mass of NaCl = 58.44 g/mol)

Answer: 0.855 mol

Question 2: Determine the mass of calcium carbonate (CaCO₃) needed to produce 0.5 mol of calcium ions. (Molar mass of CaCO₃ = 100.09 g/mol)

Answer: 50.0 g

Question 1: Design a simple experiment to test the solubility of an ionic compound in water. Outline the variables involved and safety precautions.

Answer: Students should measure a fixed amount of ionic compound, add water at a specified temperature, stir, and observe solubility. Variables include amount of compound, water temperature, and stirring time. Safety precautions include wearing gloves and goggles to handle chemicals safely.

Question 1: A sample of an ionic compound dissolves completely in water, conducts electricity, and has a high melting point. Based on this data, describe the key properties that confirm it is an ionic compound.

Answer: It dissolves completely, conducts electricity, and has a high melting point, indicating strong electrostatic forces between ions and typical ionic behaviour.

Question 1: Explain how the electrostatic attraction between ions influences the physical properties of ionic compounds. (6 marks)

Answer: The electrostatic attraction between oppositely charged ions creates a strong bond that results in high melting and boiling points, as significant energy is required to overcome these forces. This attraction also leads to the formation of a regular lattice structure, contributing to the solidity and brittleness of ionic solids. Additionally, the strong ionic bonds make these compounds soluble in water and allow them to conduct electricity when molten or in solution, as ions are free to move.

Question 1: Provide an example of an ionic compound used in industry and explain how its properties are beneficial for that application.

Answer: Sodium chloride (table salt) is used in food preservation and seasoning due to its solubility, high melting point, and ability to conduct electricity in solution, which is useful in various industrial processes.