1. Ch. 10 Representative Gases
Oxygen  02
2 molecules of oxygen
What you breathe
Ozone is a gas as O3
3 molecules of oxygen
Ozone filters out U.V. light
O2 & O3 are allotropes
They have 2 or more different molecular forms of the element oxygen.

2. Oxygen is needed for life, combustion of fuels, and energy.
The ozone is destroyed by CFC’s, CO2, and other pollutants
O3  O2 + O
Pollutants break down the ozone
This may cause global warming
Oxygen is the most abundant element per mass on Earth.

3. An oxide is a compound that contains O, which has a –2 charge.
O2 is a peroxide
A peroxide is a compound containing O2, which has a –1 charge.
Which group is oxygen most likely to form with ?
Group 2 (+2 charge)

4. Hydrogen Hydrogen is the most abundant element in the universe.
Hydrogen is a highly efficient fuel in the form of a gas.
Hydrogen may one day replace natural gas if scientist figure a way to use hydrogen, so it is not as explosive.
Hydrogen is the least dense element.
Hydrogen is found in more compounds than any other element.

5. Nitrogen
Nitrogen as a gas is N2. It is the most abundant gas in the Earth’s atmosphere.
Approximately 80 % atmosphere is nitrogen.
Ammonia, which is made up of nitrogen and hydrogen is an important fertilizer.
Nitrogen and Hydrogen are both odorless, colorless, and tasteless gases.
Liquid nitrogen is formed at temperatures less than –195 degrees C.

6. Ammonia is a colorless gas with a strong odor and is harmful in high concentrations.
Ex. Household ammonia
Production of ammonia
Haber process
N2 + 3H2  2NH3

7. Carbon Dioxide
Plays a major role in supporting plant life and our life. Without plants we wouldn’t survive.
We breathe out carbon dioxide as a waste product, which plants use for photosynthesis.
6CO2 + 6H2O  C6H12O6 + O2
Do you go a day without using plants?

8. What produces more CO2? What reduces CO2?
CO2 breaks down the ozone layer.
Carbon dioxide acts as an insulator in the Earth’s atmosphere. The U.V. light that gets into the Earth’s atmosphere has a hard time getting back out of the atmosphere.

9. Carbon dioxide is a colorless gas with a bit of a sour taste.
Carbon dioxide does not combust or burn.
Carbon dioxide as a solid is dry ice
-78.5 degrees C
Carbon dioxide as a liquid is in fire extinguishers
Helps to reduce combustion
Carbon dioxide as a gas is in pop.

10. Carbon monoxide (CO) is a highly toxic compound produced as a by-product of many human activities and machines.
CO is a poisonous gas.
CO is a colorless, tasteless, and odorless gas
Hard to detect
Causes nausea and head-aches