九年级(上)化学2《我们周围的空气》原声课堂（Ninth grade chemistry 2 the air around us soundtrack class）.doc

九年级(上)化学2《我们周围的空气》原声课堂（Ninth grade chemistry 2 the air around us soundtrack class） Air speakers around us: fu jun The second element of the content feed Understand the main ingredients of air. 2. Understand the main physical properties and USES of oxygen, nitrogen and rare gases. 3. Understand the concept of pure substance and mixture. 4. Understand the hazards of air pollution and know that air is a precious natural resource. 5. Know that oxygen can react with many substances, and the chemical nature of oxygen is more lively. 6. Understand the chemical changes, understand the basic characteristics of chemical reactions, understand the differences and connections between chemical reactions, oxidative reactions, slow oxidation and other concepts. 7. Master the laboratory method of oxygen, understand the industrial method of oxygen. 8. Understand the decomposition reaction and understand the catalyst and catalysis. 9. Understanding the conditions of combustion and combustion, understanding the explosion, slow oxidation and spontaneous combustion. Second, the key difficulty content explains (1) air The determination of oxygen content in the air. Two hundred years ago, French chemist Lavoisier studied the composition of the air in a quantitative way. Mercury has been heated in a closed container, The red powder is oxidized to mercury, and the red powder is heated, and the mercury and oxygen are obtained. The expression of these two reactions is: [pic00000. BMP] 2. The main components and composition of air Air composition (volume fraction), nitrogen (78%), oxygen (21%), rare gases (0.94%), carbon dioxide (0.03%), other gases and impurities (0.03%). (2) pure substance, mixture. A pure substance consists of a substance. It can be represented by specialized chemical symbols. It has a fixed composition, it has certain properties. Oxygen (O [pic00001. BMP]), nitrogen (N [pic00001. BMP]), carbon dioxide (CO [pic00001. BMP]). A mixture is a mixture of two or more substances. W