From Atoms to Materials

C. History of the use of metals (p. 72) 8. The order that metals were discovered and used by humans depends on: • their abundance in the Earth’s crust; and • the ease of extraction from their ores. D. Alloys (p. 75) 9. An alloy is a uniform mixture of a metal together with one or more elements. It has improved properties over its constituent elements. 13.6 Crude oil and plastics A. What does crude oil contain? (p. 81) 1. Crude oil is a mixture of many compounds. Most of these compounds are hydrocarbons. 2. Hydrocarbons are compounds made up of the elements hydrogen and carbon only. They exist as molecules. 3. In general, the larger a hydrocarbon’s molecular size, the higher its boiling point. B. How to separate hydrocarbons in crude oil? (p. 83) 4. Crude oil can be separated into fractions of different boiling point ranges by fractional distillation. C. Uses of crude oil fractions (p. 87) 5. Crude oil is a very important source of fuels. It is also an important source of raw materials for making many products, e.g. plastics, solvents and paints. D. How are plastics made from crude oil? (p. 91) 6. Plastics are made by polymerization, in which many small molecules (monomers) join to form large molecules (polymers). E. Examples of common plastics (p. 93) 7. There are many types of plastics. Their uses depend on their particular properties. Chapter Review 110 © United Prime Educational Publishing (HK) Limited 2024 All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publisher. Sample