GE-CHEM 1103 Module 7

Question 1

may be the least weighty part of the environment, but it is complex
and has a disproportionately large influence on our planet

Answer 1

Atmosphere

Question 2

total mass of the atmosphere

Answer 2

5.15 ×
10^18 kg
total mass of the atmosphere

Question 3

the best-known
changes to the atmosphere

Answer 3

increase of CO2
in the atmosphere and the
decrease of ozone in the stratosphere

Question 4

The Gases of the Atmosphere

Answer 4

Nitrogen (N₂) 780,840 ppm
Oxygen (O2) 209,460 ppm
Argon (Ar) 9,340 ppm
Carbon dioxide (CO₂) 397 ppm
Neon (Ne) 18 ppm
Helium (He) 5.2 ppm
Methane (CH4) 1.8 ppm
Krypton (Kr) 1.1 ppm
Hydrogen (H₂) 0.5 ppm
Ozone (O3) 0.4 ppm
Dinitrogen monoxide (nitrous oxide, N₂O) 0.3 ppm
Carbon monoxide (CO) 0.1 ppm
Xenon (Xe) 0.09 ppm
Radon (Rn) traces ppm

Question 5

arose from the out-gassing of Earth
when it was simply a molten mass.

Answer 5

Nitrogen

Question 6

is not the direct source of this element in living beings

Answer 6

Gaseous N2

Question 7

nitrogen must be in the form to be taken by plants.

Answer 7

usable nitrogen compound, such as
ammonia or ammonium or nitrate ions

Question 8

Two German chemists, devised a way to
transform nitrogen in the air into fertilizer, using what became known
as the Haber-Bosch process

Answer 8

Fritz Haber and Carl Bosch

Question 9

method of directly synthesizing ammonia from hydrogen and nitrogen

Answer 9

Haber-Bosch process (https://www.youtube.com/watch?v=o1_D4FscMnU)

Question 10

involves nitrogen fixation
by soil bacteria or, in aquatic environments, by
cyanobacteria.

Answer 10

Nitrogen Cycle

Question 11

Steps of Nitrogen Cycle

Answer 11

• The NH4+ ions produced are converted to
  nitrate ions, the main form of nitrogen
  absorbed by plants
• Nitrogen is returned to the atmosphere by denitrifying bacteria, which convert nitrate ions to N2
• Fixation is a chemical process that intends to “lock” tissue, cells, and subcellular
  components as close as possible to its original status
• Nitrification is a microbial process by which reduced nitrogen compounds (primarily ammonia) are sequentially oxidized to nitrite and nitrate.

Question 12

had a dramatic effect on
the atmosphere, changing it from a reducing to an oxidizing one

Answer 12

plant life

Question 13

first began producing oxygen as
long ago as 3.5 billion years

Answer 13

Blue-green algae, or cyanobacteria

Question 14

Below 17% humans would suffocate, and above 25% all organic
material would burn easily

Answer 14

Oxygen level in the atmosphere

Question 15

by-product of plant photosynthesis

Answer 15

Oxygen

Question 16

chemical reaction of photosynthesis

Answer 16

6CO2 + 6H2O → C6H12O6 glucose + 6O2

Question 17

acts as a shield from the UV-rays in stratosphere. However, it is also a pollutant in troposphere

Answer 17

Ozone (O3)

Question 18

a legal limit for exposure to ozone in the
workplace

Answer 18

0.1 ppm

Question 19

is reduced proportional to the level of ozone in the air

Answer 19

Plants growth

Question 20

Ozone can be formed in two chemical process

Answer 20

1. Dissociation of NO2 by ultraviolet rays:
   NO2 + energy λ < 240 nm → NO + O
   O + O2 → O3
2. Dissociation of O2 by radiation with λ < 240 nm :
   𝑂2 + 𝑒𝑛𝑒𝑟𝑔𝑦 ↔ 𝑂 + 𝑂
   O + O2 → O3
   (Note: Ozone also dissociates when absorbs ultraviolet radiation
   with 𝜆 < 320 𝑛𝑚
   𝑂3 + 𝑒𝑛𝑒𝑟𝑔𝑦 𝜆 < 320 𝑛𝑚 ↔ 𝑂2 + 𝑂
   𝑂 + 𝑂3 → 2𝑂2)

Question 21

leakage of chlorofluorocarbons CFCs in refrigerators and other
domestic appliance causes the depletion of ozone layer

Answer 21

Ozone Hole

Question 22

Two molecules of chlorofluorocarbons

Answer 22

CFC-114 (C2Cl2F4) and CFC-12 (CCl2F2)

Question 23

When CFCs diffuse into the stratosphere, they are decomposed by
solar radiation

Answer 23

CF2Cl2 g + UV radiation → CF2Cl g + Cl(g)

Question 24

destroy large
number of ozone molecules

Answer 24

released of Cl atoms

Question 25

depletion of ozone layer is described by the chemical reactions

Answer 25

Step 1 - 03(g) + Cl(g) → CLO(g) + O2(g) Step 2 - CLO(g) + 0(g) → Cl(g) + O2(g) Step 3 - 03(g) + solar radiation → 0(g) + 02(g) Net reaction: 2 03(g) → 3 02(g)

Question 26

essential to life, has the ability to form stable compounds consisting of long chains and rings of atoms.

Answer 26

Carbon

Question 27

basis of the structures for many compounds that comprise the living cell

Answer 27

Carbon

Question 28

trapping of energy in the Earth’s atmosphere

Answer 28

greenhouse effect

Question 29

like window glass, is transparent to incoming solar radiation

Answer 29

atmosphere

Question 30

Earth to incoming solar radiation

Answer 30

solar radiation is absorbed and reemitted as infrared radiation

Question 31

Explain why the Earth is warmer

Answer 31

Gases in the atmosphere, like window glass, trap some of these longer infrared rays

Question 32

The greenhouse effect is caused by certain gases in the troposphere

Answer 32

greenhouse gases

Question 33

primary greenhouses gases

Answer 33

* Water vapor H2O * Carbon dioxide CO2 * Nitrous oxide N2O

Question 34

If Earth did not retain some energy supplied by the Sun, the average temperature would be too cold. Life would be impossible

Answer 34

Natural Greenhouse Effect

Question 35

Much of the concern about global warming surrounds the use of fossil fuels and one of their products

Answer 35

CO2

Question 36

This increased concentration will enhance the natural greenhouse effect, causing the planet’s temperature to rise.

Answer 36

CO2

Question 37

a comprehensive air quality management policy and program which aims to achieve and maintain healthy air for all Filipinos

Answer 37

Republic Act No. 8749, Philippine Clean Air Act