Environmental Chemistry Study Material PDF

Environmental Chemistry Study Material 1.1 Chemicals in the Environment In our environment, everything is made up of chemicals, which play a critical role in supporting life. Essential chemicals include carbon dioxide (CO2), water (H2O), oxygen (O2), and glucose, which are vital for life processes....

Environmental Chemistry Study Material 1.1 Chemicals in the Environment In our environment, everything is made up of chemicals, which play a critical role in supporting life. Essential chemicals include carbon dioxide (CO2), water (H2O), oxygen (O2), and glucose, which are vital for life processes. However, not all chemicals are conducive to life; substances such as sulphur dioxide and ash can have detrimental effects. The Environment Chemicals can originate from both natural and human activities. Natural sources include volcanic eruptions and forest fires, while human activities are primarily responsible for chemical emissions through processes such as the burning of fossil fuels. The Nitrogen Cycle Nitrogen is a crucial nutrient for plant growth and reproduction; however, plants cannot utilize atmospheric nitrogen (N2). This nitrogen fixation process is carried out by special bacteria that convert free nitrogen into usable compounds. Subsequently, plants absorb these fixed nitrogen compounds through the water they take in. As animals consume plants, they form complex nitrogen compounds like proteins. Microorganisms in the soil later break these down, returning nitrogen to the atmosphere and continuing the cycle. Human Activities Human activities can significantly alter environmental substances, leading to pollution, defined as any change in the environment that produces harmful conditions for living organisms. Fertilizers Fertilizers enrich the soil to enhance plant growth, but excessive use can be detrimental. Runoff can introduce excess nutrients into water bodies, leading to harmful algal blooms. Pesticides Pesticides, including herbicides, insecticides, and fungicides, are designed to eliminate pests which can harm crops or structures. However, misapplication can lead to environmental damage, as seen with DDT, which was effective in controlling mosquitoes but takes several years to degrade. Solid Waste Improper disposal of garbage can introduce harmful chemicals into our environment. While some waste is incinerated, potentially releasing pollutants, others are recycled or composted. Remaining waste is often sent to landfills, which need to be carefully managed using liners to prevent contamination. Wastewater Sewage, a type of wastewater containing dissolved and undissolved substances, requires proper treatment. Septic tanks use bacteria to decompose organic materials, while sewage treatment plants aim to remove harmful substances from wastewater before releasing it back into the environment. Industrial Processes Many industrial practices, particularly in Alberta, rely on fossil fuels, which are combustible materials derived from ancient organic matter. The burning of fossil fuels produces carbon dioxide and water as byproducts, contributing to greenhouse gas emissions. 1.2 Acids & Bases The pH scale measures the concentration of hydrogen ions in solutions, with values ranging from 0 (strong acids) to 14 (strong bases). Acids turn litmus paper red, while bases turn it blue. Neutral solutions, such as distilled water, have a pH of 7. Measuring pH pH can be measured accurately using pH meters or acid-base indicators that change color in response to pH changes. Neutralization Neutralization occurs when an acid reacts with a base, producing water and salt. This reaction typically results in a pH around 7. Antacids can neutralize excess stomach acid, while bases can be used to manage acidic spills. Acid Rain Rainwater is naturally slightly acidic due to dissolved CO2, forming carbonic acid. Industrial emissions can increase atmospheric acid levels, leading to acid rain with pH values as low as 3. Acid rain can harm living organisms and damage infrastructure. 1.3 Common Substances Essential to Living Things Living organisms require various organic and inorganic compounds to sustain life. Organic compounds are primarily carbon-based and include macronutrients essential in large amounts, such as carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, magnesium, and calcium. Micronutrients, like selenium, are necessary in trace amounts. Excess nutrients can interfere with the absorption of others; for instance, excessive potassium can hinder magnesium uptake in crops. Carbohydrates Carbohydrates consist of carbon, hydrogen, and oxygen and are fundamental sources of energy. Simple sugars can link to create complex carbohydrates like starch and cellulose, found in foods such as rice and bread. Lipids Lipids are formed from long chains of fatty acids and include fats and oils found in various foods. Both animals and plants synthesize lipids. Proteins Amino acids, comprising carbon, hydrogen, nitrogen, and oxygen, link to form proteins, necessary for tissue growth and repair, as well as for enzyme and hormone production. Dietary sources include meat, eggs, and dairy products. Nucleic Acids Nucleic acids, the most complex organic molecules in living things, are composed of ribose sugars and phosphates, forming the foundation of DNA and RNA. 1.4 How Organisms Take in Substances Plants absorb water and nutrients via three primary methods: diffusion, osmosis, and active transport. Diffusion refers to the movement of particles from areas of high concentration to low concentration without the need for energy. Osmosis specifically relates to the diffusion of water, where water moves from soil to roots similarly without energy. Active transport, however, requires energy to move particles against their concentration gradient, which can involve transporting large molecules into plant roots. In animals, food ingestion occurs through physical breakdown (chewing) and chemical breakdown (enzyme interaction). Nutrients are absorbed into the bloodstream for distribution to cells throughout the body. Additionally, a substrate is a surface where organisms live or obtain food. For example, barnacles adhere to rocks, while cheese molds derive nutrients from their surrounding materials, illustrating how various substrates can vary in nutrient richness.