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KSSM - UASA FORM 1 SCIENCE CHAPTER 7: AIR NOTES & TUTORIAL Walter Aaron Wong BSc, MSc, MRSB CHAPTER 7: AIR 1. Air is a mixture of gases. 2. Although we cannot see it, but we can feel it. 3. Air consists of many gases, dust, microorganisms, and water vapour. 4. The main compositio...

KSSM - UASA FORM 1 SCIENCE CHAPTER 7: AIR NOTES & TUTORIAL Walter Aaron Wong BSc, MSc, MRSB CHAPTER 7: AIR 1. Air is a mixture of gases. 2. Although we cannot see it, but we can feel it. 3. Air consists of many gases, dust, microorganisms, and water vapour. 4. The main composition of clean air is as follow: 5. Why is air a mixture? Composition of air does not react chemically The components of air do not always stay the same but may change from time to time. The components of air can be separated using a physical method known as fractional distillation. The physical and chemical properties of air is the same as the components of air 6. To determine the percentage of oxygen in air, we can perform an experiment. 7. Different gases in air have different functions: Oxygen Carbon dioxide Nitrogen Inert gases: The Carbon Cycle 1. The carbon cycle shows how carbon is cycled in the environment through different processes. 2. Processes that release carbon dioxide: Respiration, decomposition and combustion 3. Processes that use carbon dioxide: Photosynthesis The Oxygen Cycle 1. The oxygen cycle shows how oxygen is cycled throughout the environment. 2. Processes that produce oxygen: Photosynthesis 3. Processes that use oxygen: Respiration, decomposition and combustion Importance of the Balance of Carbon and Oxygen Cycles 1. The carbon and oxygen cycles are in balance in the environment. 2. If the cycles are disrupted, there will be environment consequences. 3. Human activities below are example of activities that can disrupt the balance of the cycles: Deforestation Open burning Excessive burning of fossil fuel 4. Ways to prevent the interference in carbon and oxygen cycles: Create more forest reserves Use renewable energy sources Practice selective logging Stop forest burning Limit the amount of carbon emission by using less fossil fuel Creating awareness campaign Combustion 1. Combustion is a chemical process that produces fire, light, and heat energy. 2. Combustion requires oxygen as a reactant. 3. Without oxygen, combustion cannot occur. 4. Generally, a combustion reaction can be represented in the equation below: 5. Combustion reactions require 3 conditions: 6. If one of the conditions above is missing, combustion cannot occur. 7. Below show 3 activities that can prove all 3 conditions must be met for combustion to happen. Activity 1: Testing oxygen as a requirement for combustion Air has 21% of oxygen. When the candle is burning, the quantity of oxygen will reduce over time. Once all of the oxygen in the jar is used up, the flame from the candle extinguishes. This proves that, oxygen is required for combustion.  Activity 2: Testing the requirement of fuel as a requirement for combustion. Candle wax acts as a source of fuel. Once the wax melts and evaporates away, the source of fuel has depleted and the fire extinguishes. This proves that, fuel is required for combustion. Activity 3: Testing heat as a requirement for combustion. When water is splashed unto a fire, the heat is reduced. When the heat source is removed, the fire extinguishes. This proves that, heat is required for combustion. Fire Extinguishers 1. Fire extinguishers are used to put out a fire. 2. Fire extinguishers can extinguish fires by removing one of the conditions of combustions. 3. If one of the conditions for combustions can be remove, the fire can also be removed. 4. There are many types of fire extinguishers. 5. Different types are used for different types of fire.  Types of fire extinguishers Different types of fire and appropriate fire extinguishers to use Parts of the fire extinguishers 6. Besides fire extinguishers, there are other ways to put out a fire. 7. Fire blankets or water sprinklers can be used to put out fire too. Fire blanket Fire sprinklers 8. Other safety features are also fixed into buildings to alert people when there is a fire. 9. Fire alarms and smoke detectors are installed in most indoor buildings. Air Pollutions 1. Air pollution is the addition of pollutants into the air that can bring about negative effects on living things and the environment. 2. Air pollutants are substances in the air that can harm living things and damage the environment. 3. Air pollution can cause a reduction in the quality of air and disrupts the balance of the ecosystem. A) Smoke, haze and soot B) Acidic gases C) Dust and dirt D) Carbon monoxide and carbon dioxide E) Cigarette smoke  F) Radioactive waste Steps in Preventing Air Pollution Air pollution can be prevented or reduced through several methods: Law enforcement Planting more trees and creating more forest reserves Using catalytic converters in cars Raising awareness through education Recycling programs Reduce smoking habits Using public transports or carpooling