Environmental Chemistry and Nitrogen Cycle

Chemicals in the Environment

• Essential chemicals support life, including CO2, H2O, O2, and glucose.
• Other chemicals, like sulphur dioxide and ash, can be detrimental.
• Chemicals can originate from natural sources (volcanic eruptions, forest fires) or human activities (burning fossil fuels).

The Nitrogen Cycle

• Nitrogen is crucial for plant growth and reproduction.
• Plants cannot utilize atmospheric nitrogen (N2).
• Nitrogen fixation converts atmospheric nitrogen into usable compounds by bacteria.
• Plants absorb these fixed nitrogen compounds.
• Animals consume plants, forming complex nitrogen compounds (proteins).
• Microorganisms break down these compounds, returning nitrogen to the atmosphere.

Human Activities

• Human activities can significantly alter environmental substances, leading to pollution.
• Pollution is defined as any environmental change that harms living organisms.

Fertilizers

• Fertilizers enhance plant growth, but excessive use can be harmful.
• Runoff introduces excess nutrients to water bodies, causing harmful algal blooms.

Pesticides

• Pesticides (herbicides, insecticides, fungicides) eliminate pests but can harm the environment.
• Misapplication can lead to environmental damage, like with DDT (takes years to degrade).

Solid Waste

• Improper waste disposal introduces harmful chemicals.
• Some waste is incinerated or recycled/composted.
• Remaining waste is often disposed of in landfills, which need proper management.

Wastewater

• Sewage/wastewater requires proper treatment.
• Septic tanks use bacteria to decompose waste.
• Sewage treatment plants remove harmful substances before releasing treated water.

Industrial Processes

• Many industrial practices rely on fossil fuels.
• Burning fossil fuels produces carbon dioxide and water, contributing to greenhouse gas emissions.

Acids & Bases

• pH measures the concentration of hydrogen ions in solutions.
• pH scale ranges from 0 (acidic) to 14 (basic).
• Acids turn litmus paper red, bases turn it blue.
• Neutral solutions (like distilled water) have a pH of 7.
• pH can be measured using pH meters or indicators.
• Neutralization occurs when an acid reacts with a base to produce water and salt (pH around 7).

Acid Rain

• Rainwater is naturally slightly acidic (carbonic acid from dissolved CO2).
• Industrial emissions increase atmospheric acid levels, forming acid rain.
• Acid rain can damage infrastructure and harm living organisms (pH values as low as 3).

Common Substances Essential to Living Things

• Living organisms require various organic and inorganic compounds.
• Macronutrients (carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, magnesium, calcium) are needed in large amounts.
• Micronutrients (selenium) are needed in trace amounts.
• Excess nutrients can interfere with the absorption of other nutrients.

How Organisms Take In Substances

• Plants absorb water and nutrients through diffusion, osmosis, and active transport.
• Diffusion moves particles from high to low concentration without energy.
• Osmosis is the diffusion of water.
• Active transport uses energy to move particles against their concentration gradient.
• Animals ingest food, which breaks down chemically and physically to be absorbed into the bloodstream for distribution to the body's cells.

Substrates

• A substrate is a surface where organisms live or obtain food.
• Different substrates can vary in nutrient richness, impacting organisms thriving there.

Explore the essential chemicals that support life and their environmental impact. This quiz covers vital concepts like the nitrogen cycle, how pollutants affect ecosystems, and the role of fertilizers in agriculture. Test your knowledge on the balance between beneficial and harmful chemicals in our environment.