Chemistry and the Environment (Expanded) — Flashcards

Question and Answer flashcards covering environment scope, atmospheric formation and history, atmospheric composition, water properties and pollution, soil science, and soil remediation concepts.

What four components constitute the environment as defined in the notes?

Air, land, water, and climate.

How does chemistry help in environmental protection and management?

It helps understand, monitor, protect, and improve the environment; measures pollution; supports climate modeling.

What tools are mentioned for measuring pollution and modeling climate trends?

Pollution measurement devices and software models of climate trends (past, present, future).

What gases composed the primitive atmosphere about 4.5 billion years ago?

Hydrogen (H2), Helium (He), Ammonia (NH3), Methane (CH4).

What made up the secondary atmosphere before oceans formed?

Volcanic gases: water vapor (H2O), carbon dioxide (CO2), ammonia (NH3); cooling allowed oceans to form.

How did nitrogen enter the atmospheric system according to the notes?

Nitrogen arose from the breakdown of NH3 during the early atmosphere.

Which gases are listed as trace gases in the early atmosphere?

Hydrogen (H2), Methane (CH4), Carbon monoxide (CO), Hydrogen sulfide (H2S), Sulfur dioxide (SO2), Chlorine (Cl).

How did oxygen form and ozone form to make life possible?

O2 formed from photodissociation of water vapor and photosynthesis by cyanobacteria; O3 formed, providing UV shielding.

What boundary marks the edge of the atmosphere and space?

The Kármán Line.

Who measured atmospheric ozone in 1924 and with what instrument?

Gordon Dobson; ozone spectrophotometer.

What was Sydney Chapman’s contribution to atmospheric chemistry?

Theory of ozone layer formation (1930).

Who linked photochemical smog to atmospheric chemistry in 1960?

Arie Jan Haagen-Smit.

Which scientist detected CFCs in the atmosphere in 1973?

James Lovelock.

Why did Crutzen, Molina, and Rowland win the 1995 Nobel Prize?

For ozone chemistry and understanding ozone depletion.

What is the residence-time equation used in atmospheric chemistry?

Residence time = amount ÷ removal rate.

How are atmospheric gases categorized by amount and by residence time?

By amount: major vs. trace gases; by residence time: constant, variable, highly variable gases.

What is the approximate composition by volume of dry air? (N2, O2, Ar, CO2, traces)

N2 78.08%, O2 20.95%, Ar 0.934%, CO2 0.035%, trace gases ~0.001%.

What is the role of nitrogen in the atmosphere as described?

Inert, essential; fixed by bacteria/lightning; returned via denitrification/combustion.

What is the oxygen cycle in the atmosphere?

Photosynthesis and respiration cycle.

What is special about argon in atmospheric composition?

Third most abundant gas; radiogenic 40Ar from 40K decay.

Where is water vapor most abundant and what portion of the troposphere contains it?

About 90% in the lowest 5 km; 99% in the troposphere.

How much of shortwave solar and longwave radiation does water vapor absorb?

Approximately 70% of shortwave solar radiation and 60% of longwave radiation.

Why is CO2 considered a greenhouse gas and what are its sources?

CO2 absorbs infrared radiation; increased by fossil fuels, deforestation, and industry; exchanged via photosynthesis/respiration and absorbed by oceans.

Describe water’s molecular structure and bonding.

H2O with covalent bonds; bond angle ~105° in liquid, ~109°6′ in ice; polar; hydrogen bonding up to 4 bonds.

What is the density anomaly of water related to ice?

Ice expands upon freezing and is less dense than liquid water, so it floats.

What are water’s key thermal properties listed?

Specific heat 1 cal/g°C; latent heat of fusion 80 cal/g; latent heat of vaporization 540 cal/g.

Why is water a good solvent and coolant?

Water’s polarity and hydrogen bonding; high specific heat; cohesion and surface tension.

What two transport processes enable water movement in plants?

Osmosis and capillary action.

What fraction of Earth’s water is freshwater and where is most of it stored?

3% freshwater; mostly in glaciers and underground (groundwater).

What are the usable water sources for humans?

Surface water (rain, rivers) and groundwater (aquifers).

What are the three parameter categories used to describe water quality?

Physical, chemical, and biological.

What are point sources of surface pollution?

Direct discharges such as domestic and industrial waste.

What are non-point sources of surface pollution?

Indirect runoff from farms, mines, and construction activities.

What natural process contributes to surface pollution through soil erosion?

Siltation due to deforestation and soil erosion.

How can groundwater become polluted?

Seepage of sewage, fertilizers, and toxic waste into aquifers.

What are the three lake-zone layers involved in thermal stratification and their characteristics?

Epilimnion (warm, oxygen-rich), Thermocline (transition layer), Hypolimnion (cold, anaerobic).

What is dissolved oxygen (DO) and why is it important?

Essential for aquatic life; low DO causes fish kills.

What is alkalinity in water chemistry?

Buffer capacity of water, mainly bicarbonates (HCO3−).

What causes acidity in water as discussed in the notes?

CO2 forms carbonic acid; industrial sources may add strong acids.

What causes water hardness and which ions are involved?

Hardness from divalent cations: Ca2+, Mg2+, Sr2+, Fe2+, Mn2+.

What is soil composed of according to the notes?

Air, water, inorganic solids, organic matter, and microorganisms.

What is soil chemistry and what does environmental soil chemistry study?

The study of composition, properties, and reactions; environmental soil chemistry focuses on reactions with pollutants.

What are pedons and polypedons in soils?

Pedon is the smallest soil unit; polypedon is a collection of similar pedons.

Which elements dominate the Earth's crust by weight and by volume?

Oxygen (~47% by weight, ~90% by volume), then Silicon, Aluminum, Iron, Carbon, Calcium, Potassium, Sodium, Magnesium.

What are primary minerals? Give examples.

Minerals unchanged since deposition (quartz, feldspar, pyroxenes, micas, amphiboles, olivines).

What are secondary minerals? Give examples.

Products of weathering (kaolinite, montmorillonite, gibbsite, goethite, birnessite, allophane, carbonates, sulfates).

What is SOM and what are its functions in soil?

Soil Organic Matter; humus that retains water, cements soil, chelates micronutrients, buffers pH, contributes to CEC.

Name in situ soil decontamination methods.

Volatilization, biodegradation, phytoremediation, leaching, vitrification.

Name non-in situ soil decontamination methods.

Land treatment, thermal treatment, asphalt incorporation, solidification/stabilization.

What is the smallest soil unit and its counterpart in a collection of similar units?

Pedon is the smallest soil unit; Polypedon is a collection of similar pedons.

Which elements dominate the crust by weight and volume, and what is the role of oxygen?

Oxygen is the dominant element (~47% by weight, ~90% by volume); other abundant elements include Si, Al, Fe, C, Ca, K, Na, Mg.

Why is ozone important in the atmosphere?

Ozone (O3) forms in the stratosphere and protects life by absorbing harmful UV radiation (lifespan of this card reflects the note’s content).