Fig. 1 shows a sheet of graphene being considered for a touch-screen sensor. Graphene is one atom thick and contains only carbon. A research group finds tha...
Question 1 Report
Fig. 1 shows a sheet of graphene being considered for a touch-screen sensor. Graphene is one atom thick and contains only carbon. A research group finds that a very small mass of graphene can make a strong film, and that the film carries electrical signals. The group compares its properties with those of diamond, another form of carbon.
(a) Describe the arrangement of carbon atoms in graphene. [2]
(b) Use bonding to give a reason why graphene is strong. [2]
(c) How does graphene conduct electricity? [2]
(d) Give two differences between the structure of graphene and diamond. [3]
(e) Use the information to suggest two reasons why graphene is suitable for a touch-screen sensor. [2]
Answer Details
- Graphene is a single layer of carbon atoms arranged in a hexagonal network. Each carbon is bonded to three other carbon atoms. [2]
- Strong covalent bonds join the carbon atoms, and many of these strong bonds extend across the sheet. This makes graphene strong. [2]
- Each carbon atom has a delocalised electron. The electrons move through the layer and carry electrical charge. [2]
- Graphene has one layer, whereas diamond has a three-dimensional structure. Each graphene carbon atom bonds to three atoms, whereas each diamond carbon bonds to four. Graphene has delocalised electrons and conducts, whereas diamond has no delocalised electrons and does not conduct. Any three differences gain credit. [3]
- Graphene is suitable because it conducts electrical signals and is strong. It is also very thin and lightweight and can form a film. Any two valid reasons gain credit. [2]
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