Question 1: Define a giant covalent structure and explain how atomic bonding differs from simple molecular compounds.

Answer: A giant covalent structure is a large network of atoms bonded together by covalent bonds throughout the entire structure. Unlike simple molecular compounds, which consist of discrete molecules held together by weak intermolecular forces, giant covalent structures have an extensive, continuous network of strong covalent bonds, giving them unique properties.

Question 2: Name two common consumer products that utilise giant covalent structures and briefly describe their role in these products.

Answer: Diamond used in jewellery for its hardness; Graphite used in pencils for its ability to leave marks due to layered structure.

Question 3: Explain why diamond is extremely hard and has a high melting point.

Answer: Diamond's atoms are bonded by a very strong covalent network in a three-dimensional lattice, requiring a large amount of energy to break. This results in its exceptional hardness and high melting point.

Question 1: Describe how the bonding in graphite allows it to be used as a lubricant and in pencils.

Answer: Graphite's layers are made of carbon atoms bonded in a hexagonal arrangement with weak forces between layers, allowing them to slide over each other. This makes graphite a good lubricant and gives it the ability to leave marks in pencils.

Question 2: Calculate the energy required to break all covalent bonds in 1 mol of diamond, given that each C-C bond has a bond dissociation energy of 348 kJ/mol. Assume each atom forms four bonds in the network.

Answer: Total bonds = 2 * number of atoms in the network (since each bond is shared). For 1 mol of carbon atoms, total bonds = 4 bonds per atom * 6.022 x 10^23 atoms = 2 * 4 * 6.022 x 10^23. Energy to break all bonds = number of bonds * bond energy per bond = 348 kJ/mol * 4 (per atom), but since bonds are shared, total energy = 348 kJ/mol * (number of bonds / 2). So, total energy = 348 kJ/mol * 2 * 6.022 x 10^23 / 2 = 348 kJ/mol * 4 = 1392 kJ per mol of diamond.

Question 1: Design a simple experiment to test the hardness of a diamond compared to graphite. Include the variables you would control and safety precautions.

Answer: The experiment involves using a standardized hardness test, such as a scratch test, where a known force is applied to scratch each material. Variables to control include force applied, surface area, and sample size. Safety precautions include wearing eye protection and handling tools carefully to prevent injury. The expected outcome is that diamond will resist scratching, indicating higher hardness than graphite.

Question 2: Explain how the properties of giant covalent structures make them suitable for use in industry, such as in cutting tools or electronic components.

Answer: Their high hardness, strength, and thermal stability make giant covalent structures like diamond ideal for cutting tools. Their electrical conductivity, as seen in graphite, makes them useful in electronic applications. The extensive covalent bonding provides durability and stability under extreme conditions.

Question 1: A consumer reports that a jewellery piece made of a synthetic material claims to be as hard as natural diamond. If the material is a giant covalent structure, what properties would you expect it to have? Justify your answer.

Answer: The material should have high hardness and resistance to scratching, similar to natural diamond, due to strong covalent bonds. It may also have high melting point and thermal stability. Its electrical properties depend on the specific structure; if similar to diamond, it would be an insulator.

Question 2: Discuss the environmental and economic impacts of using synthetic giant covalent structures versus natural ones in industry.

Answer: Synthetic giant covalent structures can reduce the environmental impact associated with mining natural resources, such as habitat destruction and energy consumption. Economically, synthetic structures can be produced at scale, potentially lowering costs and increasing availability. However, production processes may involve high energy input and chemical use, raising sustainability concerns. Overall, synthetic options offer environmental benefits if produced responsibly and can provide economic advantages through consistent quality and supply.