Hydrogen and oxygen
Use the following data to evaluate the potential of hydrogen as a replacement for petrol and diesel to fuel cars. A complete response will include reference to advantages (6 QWC)
- A description/explanation of advantages and disadvantages of hydrogen gas as fuel for cars, based on the table which appears in the question, e.g. forms water vapour on burning so does not contribute to global warming, electricity required to produce hygrogen must be generated somehow.
- A complete response will include explanation of at least two advantages and two disadvantages.
Plastics and polymers
It has been suggested that waste plastics could be recycled and used to manufacture houses cheaply and quickly. Evaluate this potential use of waste plastics. In your answer you should refer to:
- the properties of plastics
- what happens to make plastics once they have been used
- the need to make the best possible use of the Earth's natural resources (6 QWC)
- Reference to useful properties of plastics, e.g. resistance to corrosion, insulating properties, and to those properties which are not desirable in this case, e.g. flexibility, low density.
- Reference to the fact that most waste plastic is currently disposed of in landfill sites or burnt/incererated and the associated drawbacks.
- Reference to benefits of using waste plastic, e.g. reduced amounts disposed of in landfill sites, reserves of other resources, e.g. timber and sand, are depleted less quickly/available for other uses.