Question 1: Define covalent bonding and explain how it differs in diamond and graphite.

Answer: Covalent bonding involves sharing electron pairs between atoms. In diamond, each carbon atom forms four strong covalent bonds in a tetrahedral structure, resulting in a very hard material. In graphite, each carbon atom forms three covalent bonds in a planar hexagonal structure, with weak forces between layers, making it soft and slippery.

Question 2: Describe the difference in electrical conductivity between diamond and graphite and explain the reason.

Answer: Diamond does not conduct electricity because all valence electrons are used in covalent bonds, leaving no free electrons. Graphite conducts electricity because each carbon atom has one delocalised electron that can move freely between layers.

Question 1: Calculate the tensile strength of a diamond used in a sports cutting tool if a force of 10,000 N causes it to break under a cross-sectional area of 0.0001 m². Use the formula: Tensile Strength = Force / Area.

Answer: Tensile Strength = 10,000 N / 0.0001 m² = 100,000,000 Pa (or 100 MPa)

Question 2: A graphite tennis racquet string has a length of 1.2 meters and a mass of 0.005 kg. Calculate its density. Use the formula: Density = Mass / Volume. Assume the cross-sectional area is 1 mm² and the length is 1.2 m.

Answer: Volume = Cross-sectional Area × Length = 1×10⁻⁶ m² × 1.2 m = 1.2×10⁻⁶ m³. Density = 0.005 kg / 1.2×10⁻⁶ m³ ≈ 4166.67 kg/m³.

Question 1: Design a simple experiment to compare the wear resistance of a diamond-coated sports blade versus a graphite composite blade. List the variables involved and safety precautions.

Answer: Variables include the type of blade (independent), the force applied during cutting tests, and the duration of use (dependent). Safety precautions involve wearing protective gloves and eye protection, ensuring equipment is securely mounted, and handling sharp tools carefully.

Question 2: Identify the main variable that would affect the outcome of testing the durability of a graphite hockey stick in a sports setting.

Answer: The main variable is the force or impact applied during use.

Question 1: A sports scientist tests two materials for a new tennis racquet string: diamond-like carbon coating and traditional graphite. The diamond-like coating shows a 25% higher resistance to wear after 1000 cycles. Explain what this suggests about the material's properties and potential advantages in sports equipment.

Answer: The higher resistance to wear indicates the diamond-like coating has greater hardness and durability, making it suitable for sports equipment that needs to withstand repeated impacts, such as tennis racquet strings, potentially increasing their lifespan.

Question 1: Explain how the properties of diamond make it suitable for use in high-performance sports cutting tools, and discuss any limitations it may have.

Answer: Diamond's strong covalent bonds give it exceptional hardness and thermal conductivity, making it ideal for cutting tools in sports like skate sharpening or fencing. Its brittleness and high cost are limitations, as it can fracture under impact and is expensive to produce.

Question 1: Describe how the layered structure of graphite is exploited in the manufacturing of sports equipment such as lubricants or flexible shafts.

Answer: The layered structure of graphite allows layers to slide over each other easily, making it useful as a lubricant in sports machinery. Its flexibility and ability to withstand shear forces are utilised in flexible shafts and other sports equipment components.