1. 1
   Buckminsterfullerene, C₆₀, was the first fullerene discovered. It consists of 60 carbon atoms arranged in a hollow, roughly spherical cage made up of interlocking rings of carbon atoms. Scientists are researching whether the hollow centre of C₆₀ molecules could be used to carry drug molecules to specific sites in the body.

   (a)

   Which statement correctly describes the arrangement of carbon atoms in a fullerene molecule such as C₆₀?

   [1 mark]

   • ACarbon atoms are arranged in hexagonal rings (and sometimes other ring sizes) that curve round to form a closed, hollow cage-like structure
   • BCarbon atoms are arranged in flat layers stacked directly on top of each other with no bonds between layers
   • CCarbon atoms are arranged in a rigid three-dimensional lattice extending infinitely in all directions
   • DCarbon atoms are arranged randomly with no repeating pattern at all

   (b)

   Scientists are researching whether the hollow centre of C₆₀ molecules could be used to carry drug molecules to specific sites in the body. Which property of fullerenes makes them potentially useful for this application?

   [1 mark]

   • AFullerenes are radioactive, which helps drugs travel through the body
   • BFullerenes dissolve instantly in the bloodstream, releasing their contents everywhere at once
   • CFullerenes react chemically with drugs to form a completely new, permanent compound
   • DTheir hollow, cage-like structure can enclose other molecules, such as drug molecules, inside the cage

   (c)

   Explain, in terms of its structure, why buckminsterfullerene (C₆₀) is being researched as a potential material for delivering drugs into the body.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A sports equipment manufacturer adds carbon nanotubes, a type of fullerene, to the frame of a tennis racket to make it stronger without adding much weight. Elsewhere, a chemical company uses small fullerene molecules as catalysts in an industrial reaction, taking advantage of their large surface area to volume ratio.

   (a)

   Which statement explains why carbon nanotubes are useful for reinforcing materials such as tennis rackets?

   [1 mark]

   • ACarbon nanotubes dissolve into the racket material, making it denser
   • BCarbon nanotubes are extremely heavy, adding stability to the racket frame
   • CCarbon nanotubes are long, hollow cylindrical fullerenes with very high tensile strength, so they reinforce materials while adding little mass
   • DCarbon nanotubes conduct electricity, which makes the racket frame stronger

   (b)

   A chemical company uses small fullerene molecules as catalysts in an industrial reaction. Which statement best explains why fullerenes can be effective catalysts?

   [1 mark]

   • AFullerenes are consumed and used up during the reaction, speeding it up permanently
   • BFullerene molecules have a large surface area to volume ratio, providing many sites for reacting molecules to attach to and react
   • CFullerenes are magnetic and attract reacting particles towards them
   • DFullerenes change colour during the reaction, which increases the rate

   (c)

   Explain, in terms of structure, why carbon nanotubes are useful as reinforcing fibres, and why small fullerene molecules are useful as catalysts, referring to the different property of each that makes it suitable for its use.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A lubricant manufacturer is investigating using small, ball-shaped fullerene molecules as a dry lubricant between moving machine parts, similar to how tiny ball bearings work. The manufacturer is also comparing fullerenes with graphite as an alternative lubricant.

   (a)

   Explain why the spherical shape of fullerene molecules such as C₆₀ makes them suitable for use as a lubricant.

   [3 marks]

   (b)

   The manufacturer also compares fullerenes with graphite as an alternative lubricant. Explain, in terms of structure and bonding, the similarities and differences between how fullerenes and graphite each act as a lubricant.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A pharmaceutical company is developing a new drug delivery system using buckminsterfullerene (C₆₀) cages to transport a cancer drug directly to tumour cells, reducing side effects on healthy tissue elsewhere in the body. A separate research team at the same company is developing carbon nanotube fibres to reinforce medical implants.

   (a)

   Describe, in terms of the structure of fullerenes, how this drug delivery system could work, and explain why this approach might reduce side effects compared with delivering the drug throughout the whole body.

   [6 marks]

   (b)

   A separate research team at the same company is developing carbon nanotube fibres to reinforce medical implants, such as replacement joints, so they can withstand mechanical stress without adding excessive weight to the implant. Describe, in terms of the structure of carbon nanotubes, why they are suitable for reinforcing materials such as medical implants.

   [6 marks]

   Total for question 4: 12 marks

End of questions