Chem321:Problem Set 4

Please type up your answers in Microsoft Word, Word Perfect, OpenOffice Writer or RTF file format, and email to me before midnight on Tuesday, June 21st. Do not post your answers on the wiki.

1. Define and explain briefly each of the following terms: Substitution (in context of materials), linear throughput model, technological leapfrogging , life cycle inventory, Hubbert curve (for oil), cellulose (as a renewable feedstock). 2. (~200 words) Explain what is meant by decarbonization. How is it possible that the UK underwent decarbonization in the late 20th century, yet its carbon dioxide emissions rose over the same period. 3. (~200 words) What are the main applications for the lanthanide (rare earth) metals? The prices of rare earths rose substantially in the last 2-3 years – was this caused by a shortage of minerals? Explain. 4. (~2-300 words) Discuss the value of recycling, and the limitations. Why is most used aluminum recycled, but only a little glass is recycled. 5. (~200 words) Discuss the likelihood that “biorefineries” will replace oil refineries in the 21st century. What feedstocks and products would be used/produced in the new biorefineries? 6. (~200 words) What are the differences between solar thermal and solar-photovoltaic energy production? Discuss their likely impacts in the next twenty years.