Question 1: Fullerenes are molecules composed entirely of carbon, arranged in a hollow spherical, ellipsoidal, or tubular shape. Graphene is a single layer of carbon atoms arranged in a hexagonal lattice. Describe the key structural differences between fullerenes and graphene.

Answer: Fullerenes are closed-cage molecules with a spherical or tubular shape, while graphene is a two-dimensional sheet of carbon atoms arranged in a hexagonal pattern.

Question 2: Explain why both fullerenes and graphene are excellent conductors of electricity.

Answer: Because they have delocalised electrons within their structures that allow electricity to flow freely.

Question 1: What type of covalent bonding is present in both fullerenes and graphene?

Answer: Covalent bonds between carbon atoms.

Question 2: State one physical property of graphene that results from its structure, and explain why this property occurs.

Answer: Graphene is extremely strong and lightweight due to its two-dimensional hexagonal lattice of carbon atoms, which distributes force evenly and provides high tensile strength.

Question 1: Identify two uses of fullerenes in industry or medicine and briefly explain their function.

Answer: Fullerenes are used in drug delivery systems due to their ability to trap other molecules, and in electronics as conductive materials.

Question 2: Suggest a reason why graphene is considered promising for future electronic devices.

Answer: Because of its high electrical conductivity, strength, and flexibility.

Question 1: Calculate the number of carbon atoms in a spherical fullerene molecule C60, given that each carbon atom contributes 4 valence electrons and the molecule has 60 carbon atoms.

Answer: 60 carbon atoms (the calculation is straightforward as the formula C60 indicates 60 carbon atoms).

Question 2: A sample of graphene is 1 cm² in area. If the density of carbon atoms in graphene is approximately 38 atoms per square nanometre, estimate how many carbon atoms are present in this sample.

Answer: Approximately 3.8 × 10^13 atoms (since 1 cm² = 10^14 nm², then 38 atoms/nm² × 10^14 nm² = 3.8 × 10^15 atoms).

Question 3: Describe how the structure of graphene influences its potential use in flexible electronic devices.

Answer: Graphene's flexibility, high electrical conductivity, and strength due to its thin, two-dimensional structure make it ideal for flexible electronic devices that require durability and good electrical performance.

Question 1: Propose a basic experimental approach to test the electrical conductivity of graphene sheets. Include key variables and safety precautions.

Answer: To test conductivity, connect a graphene sheet to a circuit with a power supply and an ammeter. Variables include the voltage applied and the size of the graphene sheet. Safety precautions involve handling electrical equipment carefully to avoid short circuits or shocks, and ensuring the graphene is properly supported to prevent breakage.