Test 3 - Chapter 2

how can you reduce destruction of ozone in the stratosphere?

A person can reduce ozone depletion by choosing to carpool or by taking public transportation. Walking or riding a bike does not cause smog, which deteriorates the atmosphere.

Describe the differences between oxygen and ozone (their chemical bonding, reactivity and stability)

Both diatomic ozone (O2) and triatomic ozone (O3) are made up of oxygen atoms but they have different chemical and physical properties. Oxygen is odorless while ozone has a strong, pungent odor. Ozone liquifies at -112 degrees Celsius while oxygen liquifies at a much lower temperature — -183 °C. Ozone is chemically less stable compared with oxygen. So ozone reacts more readily and at lower temperatures with other molecules. For example, ozone can react with carbon compounds at room temperature but oxygen requires more heat before it reacts.

What are the main sources of ozone formation in offices/home/ at earth's surface?

cars

health effects of ozone on people and plants.

cell damage, skin cancer, damage to the eyes, decreases plant growth

Which part of the atmosphere contains the highest concentration of ozone?

stratosphere

How is nanotechnology helping and advancing sunscreen technology?

reflecting more UV light

What are phytoplankton and why are the important to humans?

single-cell plants that convert sunlight, carbon dioxide and nutrients into the energy source for all living creatures in the throughout the world's oceans.

Describe the different UV regions and how they affect your body.

- UVA rays age skin cells and can damage their DNA. These rays are linked to long-term skin damage such as wrinkles, but they are also thought to play a role in some skin cancers. Most tanning beds give off large amounts of UVA, which has been found to increase skin cancer risk. - UVB rays have slightly more energy than UVA rays. They can damage skin cells' DNA directly, and are the main rays that cause sunburns. They are also thought to cause most skin cancers. - UVC rays have more energy than the other types of UV rays, but they don't get through our atmosphere and are not in sunlight. They are not normally a cause of skin cancer.

What is the difference between CFCs, HCFCs, and HFCs?

CFCs - containing CARBON, FLORINE and CHLORINE chemicals. has the highest ozone depleting rating (1) and is also a green house gas. HCFCs - substances containing HYDROGEN, CARBON, FLORINE and CHLORINE chemicals. has a potential to damage ozone (rating 0.05) and is also a green house gas. HFCs - ubstances containing HYDROGEN, FLORINE and CARBON chemicals. The HFC refrigerants have no ozone depletion potential, but do act as a green house gas.

describe different wavelengths of sunlight.

In order of decreasing frequency (and increasing wavelength), the various regions of the electromagnetic spectrum are: gamma rays, x-rays, ultraviolet, visible light, infrared, microwaves, and radio waves. Frequency is measured in units of cycles per second, or hertz (Hz).

How does UV radiation break the bonds of oxygen molecules?

O3 and O2 are both broken apart by UV light waves

How do oxygen and ozone act like natural sunscreen?

Ozone is found in the stratosphere, where it blocks the sun's ultraviolet (UV) waves and prevents them from reaching the earth's surface.

Describe ozone destruction.

Scientific evidence indicates that stratospheric ozone is being destroyed by a group of manufactured chemicals, containing chlorine and/or bromine. These chemicals are called "ozone-depleting substances" (ODS). - Chlorofluorocarbons (CFCs): The most widely used ODS, accounting for over 80% of total stratospheric ozone depletion. Used as coolants in refrigerators, freezers and air conditioners in buildings and cars manufactured before 1995. Found in industrial solvents, dry-cleaning agents and hospital sterilants. Also used in foam products. - Halons: Used in some fire extinguishers, in cases where materials and equipment would be destroyed by water or other fire extinguisher chemicals. In B.C., halons cause greater damage to the ozone layer than do CFCs from automobile air conditioners.

Why is the ozone concentration higher on warm sunny days as compared to rainy, cloudy days?

Since sunlight and heat are the engines that drive ozone formation, warm sunny days should have more ozone than cool or cloudy days.

How is ozone formed in the stratosphere?

Stratospheric ozone is formed naturally by chemical reactions involving solar ultraviolet radiation (sunlight) and oxygen molecules, which make up 21% of the atmosphere. In the first step, solar ultraviolet radiation breaks apart one oxygen molecule (O2) to produce two oxygen atoms (2 O).

Describe Montreal protocol

The Montreal Protocol on Substances That Deplete the Ozone Layer is a landmark international agreement designed to protect the stratospheric ozone layer. The treaty was originally signed in 1987 and substantially amended in 1990 and 1992. The Montreal Protocol stipulates that the production and consumption of compounds that deplete ozone in the stratosphere--chlorofluorocarbons (CFCs), halons, carbon tetrachloride, and methyl chloroform--are to be phased out by 2000 (2005 for methyl chloroform). Scientific theory and evidence suggest that, once emitted to the atmosphere, these compounds could significantly deplete the stratospheric ozone layer that shields the planet from damaging UV-B radiation.

Describe the relationship between ozone and global warming.

The ozone hole and global warming are not the same thing, and neither is the main cause of the other. The ozone hole is an area in the stratosphere above Antarctica where chlorine and bromine gases from human-produced chlorofluorocarbons (CFCs) and halons have destroyed ozone molecules. Global warming is the rise in average global surface temperature caused primarily by the build-up of human-produced greenhouses gases, mostly carbon dioxide and methane, which trap heat in the lower levels of the atmosphere.

Describe chapman cycle and the reaction mechanisms.

This process is considered a cycle because of its constant conversion between different molecules of oxygen. The ozone layer is created when ultraviolet rays react with oxygen molecules (O2) to create ozone (O3) and atomic oxygen (O). This process is called the Chapman cycle.

Describe visible light spectrum.

Visible light is a form of electromagnetic (EM) radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Generally, visible light is defined as the wavelengths that are visible to most human eyes. Visible light falls in the range of the EM spectrum between infrared (IR) and ultraviolet (UV).