Chemistry and the Environment Ch.2

Unit B

Organic Compounds

Compounds including Carbon, but excluding oxides (CO, CO₂) and ionic compounds of carbon based ions (carbonate).

Polymers

Carbon can bond extensively and bond together to form chains called:

Isomers

Compounds can form with same number of each type of atom but different structures.

Alkane

only single bonds between the carbon atoms; suffix is ANE

Naming alkanes:

(Number of location, if applicable)-(branch name)(parent chain)

Branch Suffix

Alkyl groups, -yl suffix

What do you do if there is more than one Alkyl branch?

Use di, tri, etc prefixes, name differing branches in alphabetical order.

Saturation vs Unsaturation

Saturated bonds are only single, unsaturated bonds are double and triple

Alkenes

Hydrocarbons containing a double c-c bond. -ene suffix, double bond location between prefix and suffix.

Alkynes

Hydrocarbons containing a triple c-c-c bond. Suffix is -yne, triple bond location between prefix and suffix

Least to most stable

Alkane, Alkene, Alkyne

Benzene Ring

Naturally occurring in petroleum and coal, carcinogenic, a persistent organic pollutant because of its stability

Functional groups

Atoms/groups of atoms that are not carbon or hydrogen

Halogenated Hydrocarbons (Halides)

Have one or more hydrogen atoms replaced by a halogen (F, Cl, Br, I). Uses prefixes chloro-, fluoro-, bromo-, iodo-.

Chlorofluorocarbons (CFCs)

A common example of an organic halide. Depletes the ozone layer by the chlorine in CFCs. Ex. Freon (refrigeration systems)

Ozone (O₃)

Reflects harmful UV rays away from the earth, important for life on earth.

How do CFCs break down the ozone layer?

The CFCs break down into chlorine, then that chlorine reacts with O₃ to create O₂ and O. The chlorine is then free to break down other O₃ molecules.

Persistent Organic Pollutants (POPs)

These stay in the environment for a long period of time, they resist breaking down and accumulate in food chains and ecosystems (biomagnification)

DDT

Used widely as a pesticide in the 50s/60s, endocrine disruptor, POP which lead to eggshell thinning in bald eagles, banned in many countries.

Polychlorinated Biphenyl (PCBs)

Used in old electric transformers, POP, no longer widely used, endocrine disruptor and neurotoxic (affects nervous system)

Dioxins and Furans

By-product of burning or industrial processes, POP, wide range of structures and toxicities, similar health affects to PCBs.

Alcohol

Organic Compound that contains the -OH functional group (hydroxyl)

Methanol

Solvents, fuels, production of pharmaceuticals, disinfectants. Extremely toxic, causes death and blindness.

Ethanol

Solvents, fuels, alcoholic beverages, production of pharmaceuticals, disinfectants, vinegar. Causes eye irritation, dizziness, headache, etc

Carboxyl Groups

Composed of a carbon atom double bonded to an oxygen atom and bonded to a hydroxyl group (-COOH). Always at the end of a carbon chain/branch. WEAK ORGANIC ACIDS.

Esters

The reaction between a carboxylic acid and an alcohol produce this & a molecule of water. Known as an esterification reaction. They are responsible for natural and artificial fragrance and flavoring in plants and fruits.

What happens during esterfication?

The alcohol loses an H and the carboxylic acid loses its OH, creating water.

Ester Suffix

-oate

Biomagnification

the process where the concentration of toxic substances (such as pesticides, heavy metals, or persistent organic pollutants) increases in the tissues of organisms as it moves up a food chain

Off-Gassing

The release of volatile organic compounds (VOCs) from building materials (“fumes”) ex: the smell of paint. Can reduce air quality and trigger allergic reactions

Volatile Organic Compound (VOC) Sources

Vehicle exhaust, cigarette smoke, building materials, household products (air fresheners), household furnishings.

Volatility

a measure of how readily a substance vaporizes or transitions into a gas or vapor phase

Incecticide

remove insects that may cause damage or disease (forestry, farming) ex: DDT (VOCs) (halogenated hydrocarbons)

Herbicide

remove unwanted plants. ex: round up, VOCs

Fungicide

protect crops and animals from fungi. Phenols (benzene ring)

Target Specificity

The range of organisms affected by a pesticide.

Toxicity

the ability of a substance to cause damage to living tissue, impair the function of a body system or cause death when ingested, inhaled, absorbed.

LD₅₀ (Lethal Dose 50)

The dosage of substance that kills half of the population

LC₅₀ (Lethal Concentration 50)

The concentration of a substance in air or water that kills half of the population

Drift

the transfer of a pesticide by wind/air currents from the location it is applied

Grasshopper Effect

transport of pesticides that results from their evaporation in warmer climates and condensation/deposition in colder climates.

Persistence

The resistance of a chemical being broken down by biological or chemical means (can result in biomagnification, see POPs)

Eutrophication

Excessive plant growth in a body of water due to rich nutrient supply (phosphorus and nitrogen) usually due to algal blooms

Biological Oxygen Demand (BOD)

a measure of the amount of oxygen required for the decomposition of organic matter in water. High BOD = High organic content

Pesticide Resistance

Genes for resistance to pesticides can be passed down to offspring

Alternative Pest Management

Pest-resistant crops, natural predation, managing habitat, monitoring crop conditions and # of pests.

Photochemical Smog (Ground level ozone)

Produced when UV light reacts with NO_x , common in large cities, brown haze that causes health issues (respiratory)