Question 1: Define an ionic compound and explain how ionic bonds are formed between ions.

Answer: An ionic compound is a substance composed of positive and negative ions held together by strong electrostatic forces. Ionic bonds are formed when electrons are transferred from a metal to a non-metal, resulting in oppositely charged ions that attract each other.

Question 2: Describe two physical properties of ionic compounds and relate these to their structure.

Answer: Ionic compounds have high melting and boiling points due to the strong electrostatic forces between ions. They are usually brittle and can conduct electricity when molten or dissolved in water because ions are free to move.

Question 3: Multiple Choice: Which of the following best explains why ionic compounds conduct electricity when molten or dissolved in water?

Answer: Ions are mobile and carry charge

Question 4: Fill in the blank: Ionic compounds tend to be ___________ (soluble/insoluble) in water, due to the attraction between water molecules and the ions.

Answer: soluble

Question 1: Design a simple experiment to test the solubility of sodium chloride in water at different temperatures. Identify the independent variable, dependent variable, and control variables. List safety precautions you would take.

Answer: The experiment involves dissolving a fixed amount of sodium chloride in water at various temperatures (e.g., 10°C, 25°C, 40°C, 60°C) and measuring the maximum amount dissolved at each temperature. The independent variable is temperature, the dependent variable is the amount of sodium chloride dissolved, and the control variables include the amount of water and sodium chloride used. Safety precautions include wearing safety goggles, handling hot water carefully, and working in a well-ventilated area.

Question 1: A student records the melting points of several ionic compounds: Sodium chloride (NaCl) - 801°C, Magnesium oxide (MgO) - 2852°C, Calcium carbonate (CaCO₃) - 825°C. Analyse these data and explain the trend in melting points based on ionic bond strength.

Answer: The melting points vary significantly, with MgO having the highest due to its strong ionic bonds resulting from the small, highly charged Mg²⁺ ion and O²⁻ ion, leading to a strong electrostatic attraction. NaCl has a lower melting point because of its single positive and negative charge ions, resulting in weaker bonds. CaCO₃ has a melting point close to NaCl, influenced by its ionic bonds but also affected by the covalent character in carbonate groups.

Question 1: Explain how understanding the properties of ionic compounds is important in the manufacturing of ceramics and glass.

Answer: Ionic compounds' high melting points and insolubility are crucial in manufacturing ceramics and glass, as they allow materials to withstand high temperatures without melting or dissolving. Their electrical insulating properties are also essential for electronic applications.