All the objects that exist around us are made up of chemical substances. These objects exist an element, compound or mixture. All these objects contribute benefit to human kind. As time goes on, human has done many researches to ensure all these chemical substances will be enough for the use of themselves. Chapter 9 of Form 4 syllabus introduces the students with manufactured substances in industry. This is important for the students to appreciate the knowledge of chemistry that is still new for themselves.
Personally, I think that this chapter is an interesting chapter as it valued the way of scientist produces the material around me. It also gives me new knowledge of the uses of chemical substances that I usually found in the laboratories. I hope, by learning this chapter, I will be more interested in learning chemistry as it will help me in the future. All the equations from this chapter make me more understand of the previous chapters. OBJECTIVES * Understand the manufacture of sulfuric acid. Synthesis the manufacture of ammonia and its salts. * Understand alloys. * Evaluate the uses of synthetic polymer. * Apply the uses of glass and ceramics. Evaluate the uses of composite materials. * Appreciate various synthetic industrial materials. Pure metal is soft and not very strong. * Atoms of pure metals have similar size and shape and are arranged closely but there is still space between the atoms. * When force is applied to pure metals, the atoms slide along one another easily. This property causes pure metal to be ductile, that is, it can be stretched into a wire. * When knocked or hammered, metal atoms slide along one another to fill spaces between the metal atoms. * This reporter causes pure metal to be malleable, that is, it can be knocked or pressed into various desired shapes. MEANING OF ALLOYS * An alloy is a mixture of two or more metals mixed in a certain percentage. OR * An alloy is a substance formed from a mixture of metal and other elements. OR * An alloy is a solid solution that contains at least one metal.
Most often an alloy will contain only two or more metals, but some alloys contain one or more metals along with a non-metal. * A foreign atom (impurity atom) may be atoms of other metals or non-metals such as carbon and silicon. The process of mixing atoms of impurities with atoms of pure metal by melting is called alloying. PURPOSES OF MAKING ALLOYS Alloys are made to * Increase the strength and hardness of the metal * Prevent corrosion of the metal * Improve the appearance of the metal so that it is more attractive.