Efecto Invernadero

Chemistry
Chapter 7 → Oxygen and Oxides

Oxygen
The composition of the air

Gas | Amount in air (%) | Amount in air (fraction) |
Nitrogen | 78.1 | About 4/5 |
Oxygen| 21.0 | About 1/5 |
Argon | 0.9 | |
Carbon dioxide | 0.04 | |

Showing that air contains about one-fifth oxygen
Using copper
You can use a silica tube to find thepercentage of oxygen in the air. The apparatus in pushed backwards and forwards over the heated copper, whic turns black as copper(II) oxide is formed.
2Cu(s) + 02(g) → 2CuO(s)

Using the rusting ofiron
You have to put damp iron wool in a test tube containing air. The iron fillings will stick to the sides.
The level of water in the tube is marked by a small rubber band. The tube is left for sometime for the iron to use up all the oxygen.
The water level rises in the tube as the oxygen is used up, and the new level can be marked using a second rubber band.

Marking oxygen in the lab

Thereaction is known as the catalytic decomposition of hydrogen peroxide.
2H202(aq) → 2H20(l) + 02(g)
Testing the oxygen → Oxygen relights a glowing splint

Burning elements in oxygen
Magnesium → brightwhite flame
2Mg(s) + O2(g) → 2MgO(s)
Sulfur → Blue flame
S(s) + O2(g) → SO2(g)
Carbon → yellow-orange flame
C(s) + O2(g) → CO2(g)

Oxides

Metal and non-metal oxides

-most metal oxides don't eitherreact with, or dissolve in, water -those that do tend to form alkaline solutions
MgO(s) +H2O(l) → Mg(OH)2 (s and aq)

-non-metal oxides often react with water to form acidic solutions – common exceptionsare water (H2O) and carbon monoxide
H2O(l) + SO2(g) → H2SO3(aq)
Non-metal oxides and the environment

Acid rain- sulfur dioxide and oxides of nitrogen

Rain is naturally acidic. But acid rain is evenmore acidic beacause of the presence of various pollutants.
→ Its caused when water and oxygen in the atmosphere react with sulfur dioxide to produce sulfuric acid.
→ Acid rain is worrying. It...