Environmental Science Overview

Water Treatment and Quality

• Water must be treated due to presence of nitrates, human and animal waste, and industrial pollutants.
• Key steps in water treatment include screening, ozone disinfection, flocculation, rapid gravity filtration, main ozone treatment for pesticides, fluoridation for dental health, carbon filtration, microstraining, chlorination, and corrosion control.

Water Types

• Pure water consists solely of H2O molecules.
• Drinking water includes additional compounds such as fluoride.

Air Composition

• The atmosphere is primarily composed of nitrogen (78%), oxygen (21%), and a trace amount of carbon dioxide (0.04%).

Catalytic Converters

• The second stage of a catalytic converter involves oxidation of carbon monoxide and hydrocarbons into carbon dioxide and water.
• Materials like platinum, rhodium, and palladium make catalytic converters expensive.

Greenhouse Gases and Global Warming

• Key greenhouse gases include carbon dioxide, methane, chlorofluorocarbons, and nitrous oxide.
• Sources of these gases vary: carbon dioxide (56%) from fossil fuel combustion, methane (18%) from anaerobic decay, etc.
• Increased greenhouse gas emissions enhance infrared radiation trapping, raising Earth’s temperatures.

Nitrogen Cycle

• The nitrogen cycle is crucial for plant growth.
• Nitrogen in the atmosphere stands at 78%, and plants derive nitrogen from nitrate ions in the soil.
• Denitrifying bacteria replace nitrogen in the atmosphere, while decaying organisms replenish nitrogen in the soil.

Resources

• Nonrenewable resources are finite and depleting faster than replenishment.
• Renewable resources have an inexhaustible supply, while potentially renewable resources can be depleted through overuse.

Pollution Issues

• Global warming causes glaciers to melt, sea levels to rise, and unfavorable climate changes affecting agriculture.
• Land pollution leads to habitat destruction and methane production via anaerobic decay.

States of Matter

• Solids have a fixed volume, high density, definite shape, and do not flow.
• Liquids possess a fixed volume, moderate density, take the shape of their container, and flow easily.
• Gases have no fixed volume or shape, are low-density, and flow easily.

Changes in Matter

• Sublimation is the direct transition between solid and gas phases.
• Impurities affect boiling/melting points and state changes.
• A chemical change involves breaking atomic bonds while a physical change entails rearranging molecules without altering them.

Separation Techniques

• Various methods exist for separating mixtures: centrifugation, crystallization, chromatography, and distillation, each suited for different states and types of substances.

Compounds and Mixtures

• An element is a pure substance with one type of atom, while a compound is formed from two or more elements chemically combined.
• Mixtures consist of multiple substances mixed but not chemically bonded, allowing for separation through physical methods.

Kinetic Theory

• All matter consists of small particles constantly in motion, with particle energy and freedom of movement varying across solids, liquids, and gases.
• As temperature increases, particles gain energy and move more vigorously, leading to changes in state, such as melting or evaporation.