Chapter 4 Practice Paper: Allotropes of carbon and nanoparticles — question paper

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

1. 1

   A graphite crystal is examined atom by atom. Each atom in a hexagonal ring is joined directly to

   1. Atwo other atoms
   2. Bthree other atoms
   3. Cone other atom
   4. Dfour other atoms
   ( )
2. 2

   Which allotrope of carbon conducts electricity?

   1. ADiamond
   2. BNeither
   3. CGraphite
   4. DBoth equally
   ( )
3. 3

   The layers in graphite slide over each other easily because

   1. Ano covalent bonds join the layers to each other
   2. Bthe C–C bonds are weak
   3. Cthe layers carry opposite charges
   4. Delectrons push the layers apart
   ( )
4. 4

   Buckminsterfullerene has the formula

   1. AC₂
   2. BCH₄
   3. CCO₂
   4. DC₆₀
   ( )
5. 5

   Which particle size range describes a nanoparticle? [Chemistry only]

   1. A100–2500 nm
   2. B1–100 nm
   3. C2500 nm and above
   4. Dbelow 0.1 nm
   ( )
6. 6

   A cube of side 1 mm has SA 0.06 cm² and volume 0.001 cm³. Its SA:V ratio is [Chemistry only]

   1. A0.06:1
   2. B6:1
   3. C60:1
   4. D600:1
   ( )
7. 7

   Nanoparticle catalysts are effective because [Chemistry only]

   1. Aa large fraction of their atoms sit on the surface
   2. Bthey melt at low temperatures
   3. Cthey carry positive charge
   4. Dthey are denser than bulk catalysts
   ( )
8. 8

   Graphene is useful in flexible electronics because it

   1. Ais the softest allotrope
   2. Bconducts and is one atom thick
   3. Ccontains metallic bonds
   4. Dmelts at room temperature
   ( )
9. 9

   One risk of nanoparticle use in consumer products is that [Chemistry only]

   1. Athey are always radioactive
   2. Bthey explode in air
   3. Ctheir long-term health effects are unknown
   4. Dthey cannot be removed from products
   ( )
10. 10

    Diamond drills cut rock effectively because diamond

    1. Ahas layers that slide
    2. Bconducts heat to the rock
    3. Cis a very soft mineral
    4. Dis the hardest natural substance, with bonds in all directions
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 11

   Two carbon electrodes carry current through molten potassium chloride in an electrolysis cell.

   1. (a)

      Explain why graphite can carry the current, referring to its structure and bonding.

      [3]
   2. (b)

      Explain why diamond could not replace graphite here.

      [2]
   3. (c)

      State one other property that makes graphite suitable for electrodes in hot cells.

      [1]
2. 12

   A company makes a sports racket from a plastic filled with 3% carbon nanotubes, and compares it with the plain plastic.

   Racket frame test results

   Frame	Mass / g	Breaks under force / N
   Plain plastic	96	410
   Nanotube-filled plastic	98	1150

   1. (a)

      Calculate how many times stronger the filled frame is, and comment on the mass cost.

      [2]
   2. (b)

      Explain why nanotubes add so much strength for so little mass.

      [2]
   3. (c)

      State one other use of nanotubes or fullerenes. [Chemistry only]

      [1]
   4. (d)

      Suggest why a rival maker’s claim of “1000× stronger frames” using only 0.5% nanotubes should be treated with caution. [Chemistry only]

      [2]
3. 13

   A class investigates the surface-area-to-volume ratio using cubes of modelling clay. [Chemistry only]

   1. (a)

      A cube has sides of 2 cm. Calculate its surface area, its volume and its SA:V ratio.

      [3]
   2. (b)

      The cube is re-cut into eight cubes of side 1 cm. Calculate the new total surface area and ratio, and state the change.

      [2]
   3. (c)

      Explain why a catalyst cut this way reacts faster.

      [2]