Raw materials are natural resources that are converted into finished goods through manufacturing. Materials can be classified into five groups based on their properties and how they are obtained and processed. Material properties include technological properties like malleability, fusibility, and ductility; physical properties like density; and mechanical properties like hardness, tenacity, and elasticity. Material properties also include important physical and chemical attributes like thermal conductivity, thermal expansion, melting point, electrical conductivity, oxidation, and corrosion. Obtaining raw materials can negatively impact the environment through depletion of natural resources and pollution from human activities in mining and processing.

1. UNIT 4
Answer these questions in your A5 size pages. Copy the headings.
1. What are raw materials? Write some examples. Page 62.
2. From a technical point of view we can classified materials into five groups. Copy the table you
can find in page 63.
3. What are material properties? Page 64.
4. Material properties can be classified into three groups
4.1 Technological properties. Page 66.
Explain the following properties
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Malleability
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Fusibility
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Ductility
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Weldability
4.2 Physical properties Page 67
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Density
4.3 Mechanical properties Page 67
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Hardness
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Tenacity
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Elasticity
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Mechanical resistance
4.4 Physical and chemical properties. Page 68
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Thermal conductivity
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Thermal expansion
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Melting point
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Electrical conductivity
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Oxidation
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Corrosion
5. The environmental impact of obtaining materials. Page 72

2. •
What are the two causes of environmental impact?
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How are the environmental repercussions caused by human actions?