What is Environmental Chemistry?
Environmental chemistry studies the chemical processes in air, water and soil, and how pollutants harm ecosystems. It bridges chemistry, biology and geology to understand climate change, water quality and air pollution.
Environmental chemistry applies chemical knowledge to environmental problems: analyzing pollutants, understanding transformation reactions, and designing cleanup methods for a sustainable world.
- 1.Emission — Industrial, vehicle and natural sources release pollutants
- 2.Transport — Wind and water currents carry pollutants globally
- 3.Transformation — UV light, heat and reactions change pollutant chemistry
- 4.Accumulation — Pollutants settle in soil, water or organisms (bioaccumulation)
- 5.Deposition — Pollutants settle out or enter food chains
- 6.Remediation — Natural processes and human action attempt cleanup
Step-by-step worked examples
A factory emits 100 kg SO₂ daily. How much H₂SO₄ acid rain can form if all SO₂ is oxidized and dissolves in water? (Molar mass SO₂ = 64, H₂SO₄ = 98 g/mol)
Moles of SO₂ = 100,000 g / 64 g/mol = 1,562.5 mol 2 SO₂ + O₂ → 2 SO₃; SO₃ + H₂O → H₂SO₄ From stoichiometry: 1 mol SO₂ → 1 mol H₂SO₄ Moles of H₂SO₄ = 1,562.5 mol Mass of H₂SO₄ = 1,562.5 × 98 = 153,125 g ≈ 153 kg
A 50 mL water sample contains 0.5 mg Pb²⁺ ions. Calculate the concentration in ppm (parts per million). (Assume water density = 1 g/mL)
Mass of water = 50 mL × 1 g/mL = 50 g ppm = (mass of pollutant / mass of water) × 10⁶ ppm = (0.5 mg / 50,000 mg) × 10⁶ = 10 ppm
An aquifer has 200 ppm NO₃⁻ contamination. How many kg of NO₃⁻ are in 1 million liters of water?
200 ppm = 200 mg pollutant per 1000 g water 1 million liters = 10⁹ g water Mass of NO₃⁻ = (200 mg / 1000 g) × 10⁹ g = 200 × 10⁶ mg = 200 kg
Flashcards
Quick quiz
Q1.Which gas is the leading contributor to acid rain?
Q2.Bioaccumulation is a process where…
Q3.What does ppm mean in water quality?
Q4.Which refrigerant damaged the ozone layer?
The full card deck, worked steps and AI-tutor support for “What is Environmental Chemistry?” are in Notek — study by hand before your exam.
Common mistakes
Confusing ppm with percent (%) concentrations. — Correct: ppm is mg/L for dilute solutions; % is typically g/100 mL for stronger solutions.
Assuming pollutants are destroyed instantly once in the environment. — Correct: Many persist for years, accumulate in organisms and cycles through the biosphere.
Forgetting that reactions in the atmosphere transform pollutants into different compounds. — Correct: SO₂ oxidizes to SO₃, NO oxidizes to NO₂, and both dissolve to form acids.
Thinking ozone in the troposphere is beneficial like stratospheric ozone. — Correct: Ground-level ozone (from NOₓ + VOC reactions) is a harmful air pollutant.
FAQ
What are the main sources of air pollution?
Industry, vehicles, power plants and agricultural activities emit SO₂, NO_x, particulates and volatile organic compounds.
How does acid rain form?
SO₂ and NO_x gases oxidize in the atmosphere to form H₂SO₄ and HNO₃, falling as acidic rain.
What is water hardness and why does it matter?
Hardness is Ca²⁺ and Mg²⁺ ion concentration. High hardness reduces soap effectiveness and clogs pipes.
What is the greenhouse effect?
CO₂, CH₄ and other gases trap heat in the atmosphere, warming the Earth and changing climate.