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					Introduction to Chemistry

         prepared by:
 Benedicta B. Alava, Ph.D. Chem
Environment –the natural surroundings of an organism
that directly or indirectly influence its growth and
development. It includes the air, water, land, natural
resources, flora, and fauna

Classification of Environment
 1. Physical – atmosphere, hydrosphere, and lithosphere
  2. Biological – floral, fauna, and microbes
  3. Cultural – society, economy, and politics
Environmental Science
- The study of the interactions between the physical,
   chemical, and biological components of the
   environment, and their effect on living organisms.
Environmental science focuses on:
- the application of biological and chemical principles to
   study the physical environment
- the establishment of policies and solutions to existing
   environmental problems such as controlling
   environmental pollution and degradation
 - the interaction of human society and the natural
    environment
 - the preservation and management of the natural
    environment
Environmental Science is an interdisciplinary science

    Chemistry

    Physics
    Biology
    Engineering and Technology
    Social Sciences
Chemistry
  - a science
  - study of matter
  - composition, structure, behavior, properties,
     reactions, changes, energy and energy changes
Matter
- anything that occupies space and has mass
 - something that can be perceived by one or more senses
  - examples - the chair you are sitting on, the paper you
             are holding, the computer in front of you,
             the water you are drinking, and the air you
             are breathing are all examples of matter.
Composition of Matter
 - all types of matter are made up of atoms and molecules
Atom
 - is the smallest particle of an element that retains the
      properties of the whole element.
  - it can participate in chemical reactions but can no
       longer be broken down into simpler forms of matter.

   Helium Atom



   Carbon atom
Molecules
 - a group of two or more atoms of the same or different
    kinds that are chemically bonded together




                     Water – H2O




                     Carbon dioxide
Forms of Matter
   - Pure form and Impure Form
 Pure Forms of Matter
   - they are also called substances
   - particles of a certain substance are all alike.
   - they have definite composition
    - they could either be elements and compounds
  An element is made up of
  identical atoms. For example,
  the element gold should
  contain only atoms of gold. If
  the presence of another atom
  (even just one) is found, then
  this matter is no longer an
  element.
 A compound is a substance whose
 ultimate particles are made up
 only of one type of molecule. The
 compound water, H2O, must
 contain only molecules of water
 and no other.


Assessment Task
Given the formulas below, identify as to element or compound
             Cu, NaCl, CCl4, CO2, O2,
             Cl2, C6H12O6, P4, S, Al,
             HCl, H2, N2, NH3, H2SO4
             CO2 + N2
Compounds may be broken down to simpler substances
by chemical processes.
Examples:
  Sodium bicarbonate (NaHCO3) referred to as "baking
  soda" may be decomposed by heating into sodium
  carbonate (Na2CO3), carbon dioxide (CO2), and water
  (H2O)
                     ℎ������������
          2NaHCO3              Na2CO3 + CO2(g) + H2O(g)

   Cupric carbonate (CuCO3) decomposes to cupric oxide
  (CuO) and carbon dioxide (CO2).
                    ℎ������������
           CuCO3               CuO + CO2(g)
The Impure Form of Matter
- the mixture
- formed if two or more substances do not react when
   they are put together.
- examples
 - air is a mixture nitrogen (N2) and oxygen (O2) gases
 together with small amounts of carbon dioxide (CO2),
 argon (Ar), and other impurities
 - vinegar is a mixture of water and acetic acid (CH3 COOH)
 - the construction material called concrete is a mixture
 of sand, gravel, cement, and water.
Forms of Mixtures- homogeneous and heterogenoeus
 Homogeneous mixture
 - also called a solution
 - contains two or more components that are uniformly
     dispersed throughout the system
 - no differentiating parts can be observed by the naked
     eye because only a single phase mixture is formed.
 - examples of homogeneous mixtures are alloys, milk,
    vinegar, carbonated drinks, and chocolate bars.
Gold jewelries are not pure
substances. The element gold is
very malleable and ductile. It can
easily be deformed. Thus, it is
impractical to use pure gold for
jewelries. Another metal like
silver is added to reduce the
malleability of gold. This mixture
is also called an alloy. Alloys are
homogeneous solutions of two
or more solids.
heterogeneous mixture
 - the components are not uniformly dispersed
     throughout the system
 - differentiating parts can be observed by the naked eye
  - may be made up of two or more different phases
 - examples are: vegetable salads, oil and water, ice in
   water, and mixed nuts.
Gold panning is an exciting
activity of separating gold from
water and other soluble
components by the use of screen,
sieve, or classifier. Gold, being
insoluble in water, forms a
heterogeneous mixture with
water, and soil
Distinguishing Characteristics of Compounds from
                                  Mixtures
1. as to composition
  - compounds have definite compositions, mixtures
       have no definite composition
2. as to properties
    - compounds do not exhibit the same properties and
    characteristics as the substances from which they are made
   - each component of the mixture still retains the same
   chemical makeup it had prior to mixing
3. as to components recovery
 - a chemical reaction is necessary to transform back a
 compound to its original components
- mixtures can be physically separated
 Assessment Task

Classify the following materials as to element, compound,
or mixture.
  - Starch, proteins, carbohydrates, sucrose, polyethylene
     plastics, graphite, dry ice,
   - glass, quartz, cement, concrete, calcium carbonate,
     asphalt, zinc, aluminum, copper,
  - corrugated metal, steel, rubber, silk, silica, alumina,
     toothpaste, fruit juice, rocks, petroleum, diesel.
        Table 1.05. Shapes and Volumes of Matter
    Physical              Physical Characteristics
     States            Shape                Volume
      Solid      has definite shape has definite volume
     Liquid       has no definite     has definite volume
                       shape
       Gas        has no definite       has no definite
                       shape                volume
Phases of Matter
- condensed phases – solids and liquids
- fluid phases – liquids and gases
Processes of Transformation
Melting – from solid to liquid, heat is needed
        H2O(ice) + heat → H2O(l)
Vaporization – from liquid to gas, heat is needed
       H2O(l) + heat → H2O(vapor)                 Endothermic
Sublimation – from solid to gas, heat is needed
      C10H8(s) + heat → C10H8(g)

Freezing – from liquid to solid, heat is released
         H2O(l) → H2O(s) + heat
Condensation – from gas to liquid,heat is released
         H2O(g) → H2O(l) + heat                    Exothermic
Deposition – from gas to solid,heat is released
         C10H8(g) → C10H8(s) + heat
             Changes in Matter
     - physical change    - chemical change
Physical Change
 - any change that does not involve a change in the
    chemical composition of a substance
 - it does not produce a new substance because no
   chemical reaction occurs
 - the material before and after a physical change is still
    the same, even though the appearance and physical
    state may be different
- examples: crumpling a sheet of paper, casting gold
   into a mold, cutting pieces of wood, melting an ice
   cube, and other phase changes.
Chemical change
 - a change of matter into another material with different
   properties
 - new substance is formed
- there may be indicators that a chemical change is taking
   place, such as:
    Gas production – bubbling is observed when hydrogen
                     peroxide decomposes to water and
                     oxygen gas.
   Emission of odor – a rotten egg odor is produced by
                     decomposing organic matter
Increase or decrease of heat and temperature
              – Heat and energy are released during
                nuclear explosion
Color changes – Green mangoes turn to yellow as they
                 ripen
Change of form – a piece of paper turns into black
                powder after burning due to the
                formation of carbon
light and sound production – a bright light and an
                 explosive sound are observed when
                 hydrogen gas is ignited in air
All forms of matter are characterized by their properties
and behaviors as they undergo physical and chemical
changes

 Physical properties
  - can be observed or measured without changing the
     composition of matter
  - examples of physical properties include boiling point,
    freezing point, density, viscosity, melting point, and
     temperature
- other examples are brittleness, ductility, electrical
   conductivity, electrical resistivity, malleability, magnetic
   field, momentum, permeability, pressure, specific heat,
   tensile strength, thermal conductivity, and velocity
Chemical property
 - can only be observed during a chemical change
 - it is a measure of the capacity of a certain substance to
   undergo a change
 - examples are: capacity of a piece of paper to burn
 (flammability), the ability of a plant to grow
 (metabolism), the capacity of a piece of iron to corrode
 (oxidation), conversion of sugars to alcohol and acids
 (fermentation), patination of copper surfaces (oxidation)


         A
Assessments
 1. Classify the following as to chemical change or physical change.
    Justify must your answers:
    sublimation of dry ice, breaking of glass, burning of wood,
    photosynthesis, ice cream mixing, cloud formation, rotting of food,
    burning of gas fuel, inflating a rubber tire, tearing a piece of paper,
    flattening gold into sheets, food digestion, firework explosion, acid
    base neutralization, melting of ice, crushing a glass bottle
Read the paragraph below. List down all the observed changes and classify as
to chemical or physical change. List down all the observed properties
classifying them as to chemical or physical properties.

     A little girl was observing her mother preparing dinner. For the salad, the
green vegetables were cut into small cubes and mixed in a bowl. The dressing
was prepared by making an emulsion of olive oil and mayonnaise. Sugar and
vinegar were added to give the pleasant sweet and sour taste. The main
course was a very tender beef, marinated with salt and broiled to perfection in
a burning charcoal pit. For the sauce, her mother prepared her own
concoction by caramelizing honeyed syrup until the sweetness changed to a
slight bitter taste, while still maintaining its sweetness to give the interestingly
burnt odor. Side dishes were fried diced sweet potato and boiled corn in cobs.
For the cake, her mother whipped egg white in 1 liter of milk, 300 grams of
sugar, a bar of chocolate, and 3 tablespoons of vanilla into a homogeneous
mixture before cooking this in a preheated oven for 45 minutes. The little girl
was so excited that she volunteered to arrange the mahogany dinner table. To
accentuate the dining room she lighted small candles with a burning
matchstick and sprayed 1 mL of an herbal essential oil into the air
Energy - the ability of a system to do work on another
         system
      - energy is needed by a running person
      - energy is needed to cook food
      - energy is needed to lift a sack of rice
      - energy is needed to light an electric bulb
      - energy is needed to run a car
      - energy is needed to push a table across a room

 Classification of Energy
    - potential energy
    - kinetic energy
 Potential energy or stored energy is the energy of a system or a
 body by virtue of its position or brought about by the
 arrangement of the particles in that body or system.
  - the water in a dam exerts pressure (potential energy)
     against the wall of the dam
  - a battery has potential energy stored in the chemical
     materials inside it
  - a rock brought up and left on top of a hill gains potential
     energy due to gravity.
  - a fruit dangling from the tree has potential energy due to
     gravity
- the gas inside an unopened bottle of soda exerts pressure
   against the sealed cover.
 - an explosive has stored energy in the chemicals inside it.
 - children in a not moving position as they play the tag of war
    exerts potential energy.
 - solar panels have stored energy from the sun.
Kinetic energy is the energy of a system or body with respect its
motion or to the movement of the particles inside it.
  -   the energy possessed by a running car maybe strong
      enough to knock off a person.
 -    the energy possessed by the water of Maria Cristina falls can
      rotate a turbine that can generate electricity to communities
      below it.
 - the energy of strong winds may be used to rotate windmills

 -    children jumping on a trampoline exert energy to counter
      gravity
- a person needs kinetic energy as he lifts an object from the
  ground to the table
Atmosphere
  - a layer of gases (air) at the surface of the earth.
   - a protective covering of earth’s life against solar
     radiation and excessive heating
Composition of Dry Air
  Gas                                  % by Volume
  Nitrogen, N2                         78.03
  Oxygen, O2                           20.99
  Argon, Ar                            0.94
  Carbon dioxide, CO2                  0.033
  Neon, Ne                             0.0015
  Helium, He                           0.000542
  Krypton, Kr                          0.00014
  Xenon, Xe                            0.000006
  Source: Chang, R. Chemistry, 7th ed., McGraw-Hill, 2002
Nitrogen
 -     nitrogen is the most abundant element in the atmosphere
       but, its diatomic form, N2, is relatively inert
 -  it is not easily assimilated by living organisms and does
    not easily react with other chemicals to form new
    compounds
 - it has to be transformed into its reduced forms (such as
    ammonia, ammonium, nitrates, nitrites, and nitrogen
    oxides)
- the process of nitrogen fixation transforms this diatomic
   nitrogen to other compounds of nitrogen to be used in the
   formation of biological compounds (such as nucleic acids,
   amino acids, and proteins), industrial compounds (such as
   potassium nitrate for gun powder, nitroglycerin and nitro-
   toluene, and fertilizers), and many more.
     - nitrogen fixation can be natural or synthetic
Examples of Nitrogen Fixation
1. Nitrogen fixation brought about by lightning
        Steps: N2(g) + O2(g) electrical energy 2NO(g
•)              2NO(g) + O2(g)                                  2NO2(g)
               2NO2(g) + H2O(l)                          HNO2(aq) + HNO3(aq)

2. Biological Fixation of Nitrogen, BFN
     - Organisms such as the Cyanobacter, Azotobacter, and
     Azospirillum can produce the enzyme nitrogenase which
                                             )

     they use catalytically for the conversion of atmospheric N2
     to NH3. Another group of organism, the Rhizobium works
     symbiotically with legumes and other plants to reduce N2.
                           ��������������������������������������������
              N2 +   8H+                            2NH3 + H2
3. Synthetic Fixation by Haber-Bosch Industrial Process
                 N2(g) + 3H2(g) → 2NH3(g)

 The Nitrogen Cycle
      Nitrogen in its consumable form is made possible by
  the process called the nitrogen cycle, in which nitrogen
  is taken from the atmosphere and converted to nitrates
  by nitrogen fixation.
       The nitrates are absorbed by plants converting them
  to proteins and nucleic acids which are further eaten by
  animals
      Eventually the nitrogen from the plants and animals
  (together by industrial nitrogen) is converted to N2 by
  another group of microorganisms called the denitrifying
  bacteria.
The Nitrogen Cycle
 The Atmospheric Oxygen
- dry air contains approximately 20.99% O2 by volume
- a very reactive element, it easily reacts with other
   elements or substances and disappears from the
   atmosphere
- its concentration in the atmosphere is almost always
  constant
      Oxygen is removed mainly from the atmosphere by
                   respiration
      The main route for the regeneration of the diatomic
      oxygen into the atmosphere is by the process of
                photosynthesis
     This continuous cycling of oxygen through these two
     processes for the stable concentration of oxygen in the
     atmosphere.
Respiration is the process by which energy is released from
the cellular oxidation of glucose in a process called
glycolysis

   Equation: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

Photosynthesis is the process by which plants convert light
energy to chemical energy (stored in the chemical bonds of
sugar) with the simultaneous release of oxygen gas.

   Equation: 6CO2 + 6H2O + energy → C6H12O6 + 6O2
Layers of the Atmosphere
1. Troposhere          3. Mesosphere
2. Stratosphere        4. Ionosphere
  Troposphere
 - thinnest layer, extends up to 10 - 11
 km from the earth’s surface
- most dense, contains 80% of
      air mass
 - where all weather changes are
 observed, a region of rising and
 falling of packets of air
 - air pressure at the topmost
 part is 10% of that at sea level.
 The atmospheric pressure at sea
 level is 1 atm.
  - temperature is highest at the lowest portion and decreases with
                increasing altitude
 -   tropopose is the zone separating the troposphere from the
     next layer, the stratosphere.
Stratosphere
- situated between 10 – 50 miles from
the earth’s surface
- where the ozone layer is found
-vertical stratified in temperature, with
warmer layers higher up and cooler layers
farther down. The topmost is about -30C
 - the formation of ozone from atomic
 oxygen and diatomic oxygen is exothermic.
 Ozone also absorbs ultraviolet rays turning
 them to heat energy. Thus, temperature
 increases towards the top of this layer
 where the ozone molecules concentrate.
 - The vertical stratification,reduces temperature convection. Thus no
 associated turbulence is observed, making this layer dynamically stable. For
 this reason, airplanes prefer to fly at the lower portion of the stratosphere.
 Balloons and other gliders can go as far as the lower portion of the
 stratosphere.
- The boundary between the stratosphere and the next layer is called the
    stratopause
Mesosphere
  - the mesosphere starts at 50 km
  above Earth's surface and goes up
  to 85 km high.
- temperature decreases with
altitude. The top of the
mesosphere is the coldest part of
Earth's atmosphere, around - 90° C.
 Most meteors from space burn
 up in this atmosphere
 Not so much is known about this layer because research
 instruments cannot easily be sent and maintained at this
 level.
  Mesopause is the layer that divides the mesosphere and the
  next atmosphere.
Thermosphere (ionosphere)
- extends from 85 -90 km to 500 -
1,000 km above the earth’s surface.
- temperature increases with
altitude with temperature (500°C -
2,000°C).
- the air density is very thin.
- temperatures can go very high
but one would not feel warm in the
thermosphere because there is so
few contact with the atoms of the
thin air.
- sound transfer would also be very
low because of very infrequent
molecular collision
Thermosphere (ionosphere)
- where the space shuttles orbit
    the earth
 - most of the ultraviolet rays and
 light photons from the sun are
 absorbed in this layer

 - the UV rays ionize the gases
 excited ions. and O2.
   N2 → 2N             ΔH = 941.4 kJ
    N → N+ + e-        ΔH = 1400 kJ
           +
   O2 → ����2 + e-       ΔH = 1176 kJ
- results of ionization
1. High temperature        2. Radiowaves   3. Aurora phenomenon
                                              N+ , violet to blue
                                                +
                                              ����2 - green to red
The Ozone Layer
 - ozone is a triatomic molecule = O3
 - a blue colored gas with a very strong burnt odor

 - most ozone molecules are found in the stratosphere at
 2-8 ppm concentration
 - the ozone layer absorbs much of the ultraviolet rays from
 the sun, preventing these rays from reaching the planet’s
 surface.
 - ultraviolet rays has been found to cause skin cancer,
 cataracts, and other genetic mutations both in animals
 and plant
Ozone , O3
    - Pale blue gas (O3) that is irritating, explosive, and toxic.
    - It is formed by the photochemical action on the atmosphere
                     UV
     O2 (in air)            O+O
             O 2 + O → O3

    -May also be manufactured on the spot by passing an electric discharge through
     oxygen or air

    -it is used in water purification, deodorization, bleaching, and various chemical
     reactions that require a strong oxidizing agent

      compared to chlorine, bacterial and viral disinfection with ozone is up to
       5000 times more rapid.
Good Ozone or the ozone layer
    – occurs in the stratosphere
    -maximum ozone concentration is 5 × 1012 molecules/cm3
     (more than 1000 times the the concentration of bad ozone at earth's surface)
    -This layer (atmospheric ozone) absorbs 97–99% of the sun’s high frequency
     ultraviolet light (UV) which is damaging to life on Earth.[

       overexposure to UV is believed to be contributing to the increase
         in melanoma, the most fatal of all skin cancers.
         UV can also damage sensitive crops, such as soybeans, and reduce
         crop yield

   - Depletion of this ozone layer may increase the incidence of skin cancers.

       ozone-depleting substances (ODS), includes chlorofluorocarbons (CFCs),
        hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon
         tetrachloride, and methyl chloroform.
- Bad ozone

  Located at the troposphere layer at a usual concentration of 0.02 -0.03 ppm

  In polluted places such as cities where there are high densities of smog, O3
       concentration could go higher than 0.1 ppm
  At concentrations greater than 0.1 ppm, ozone is toxic and can be a
    potent bronchial irritant, making breathing difficult.
  it also damages crops, trees and other vegetation.

  Ground-level or "bad" ozone is the product of the chemical reactions between
   oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence
   of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle
    exhaust, gasoline vapors, and chemical solvents are some of the major
    sources of NOx and VOC

    Photochemical smog contains a high concentration of O3
          “smog” – mixture of smoke and fog
How the ozone layer absorbs UV radiations
Step 1. Photodissociation of O2 by solar UV radiation (ʎ < 240 nm).
                           ��������
                      O2          O+O
Step 2. An oxygen radical combines with another O2 to form an
ozone, O3, molecule.
                  O + O2 + M → O3 + M
Step 3. Now the O3 absorbs UV radiations (ʎ = 200 to 300 nm) and
                          ��������
dissociates          O3          O2 + O

Step 4. The cycle of steps 1 to and 3 is repeated all over or
simultaneously occuring.
 This dynamic equilibrium process of generation and destruction of
 O3 by UV radiation accounts to the almost constant concentration
 of ozone molecules in the stratosphere.
Depletion of the Ozone Layer
ODS - ozone depleting substances
    - group of chemicals containing chlorine (Cl) and bromine (Br)
    - these are the chloroflourocarbons (CFC),
        hydrochloroflourocarbons (HCFC)
        carbon tetrachloride (CCl4)
        bromoflourocarbons,
        hydroflourocarbons, and
        oxides of nitrogen (NOX)
     - they are commonly used as coolants, refrigerants, aerosol
       propellants, foams, fire-fighting chemicals, soil
       fumigants, and solvents
The choroflourocarbons (CFC)
 - examples: CFCl3 (Freon 11)
             CF2Cl2 (Freon 12)
             C2F3Cl3 (Freon 113) and
             CF4Cl2 (Freon 114)

 - when these substances are discharged in the
 atmosphere, they remain stable for long periods of time.
 - when they reach the ozone layer, they react with the ozone
 molecules.
Depletion of the ozone layer by CFC’s
                                       ��������
 1. CFCl3 is decomposed by UV: CFCl3          CFCl2 + Cl
 2. The radical Cl reacts with O3:    Cl + O3 → ClO + O2
 3. The radical ClO takes
    another O radical from
    the atmosphere:              ClO + O → Cl + O2
 4. The regenerated chlorine radical takes another O3 and
    the cycle is repeated
 5. The Cl radical catalyzes the decomposition of O3 much
     faster than the decomposition of O3 by UV.
  6. One Cl radical can destroy up to 100,000 ozone
     molecules before it is consumed by other reactions.
Depletion of the Ozone Layer by NOX
 - NOx, such as NO and NO2 are products of fuel gas
 combustion
 - Most of these NOx are released to the atmosphere by
 supersonic aircrafts
                                ��������
   - Reactions:             O3       O2 + O
                      NO + O3 → NO2 + O2
                       NO2 + O → NO + O2
                  Overall: 2O3 → 3O2

  Nitrogen dioxide (NO2) can reacts with the radical ClO
 forming chlorine nitrate, a very stable chlorine reservoir in
 the atmosphere. NO2 + ClO → ClONO2
 Clorine nitrate(ClONO2) is a source of Cl in the formation
 of the ozone holes in the arctic and antarctic skies
The Polar Ozone Holes
  - the repeated abnormal depletion of the ozone layer (to as
  much as 50%) over the arctic and antarctic regions during
  spring time




                               One DU is 2.69×1016 ozone molecules per cm2
The Antarctic ozone hole is an area of the
Antarctic stratosphere in which the recent ozone
levels have dropped to as low as 50% of their
pre-1975 values.
 During winter, polar stratospheric cloud
 Containing HCl and chlorine nitrate (ClONO2) is a
 Good source of Cl radical which reacts
 with ozone
Types of energy manifested by atoms and molecules:
   electronic energy ≈ absorbed at UV and VIS wavelength (ex: light radiation)
   vibration energy ≈ absorbed at IR or far IR wavelength (ex: heat radiation)
    rotational energy ≈ absorbed at the longer wavelengths like micro, radio, etc.)

 How heat is generated

   As the UV and VIS rays strike the surface of the earth, earth molecules
     start to vibrate. This process produces another form of energy (heat energy).
     The earth surface releases this heat energy above the surface of the earth.
Greenhouse gases are largely transparent to shortwavelengths like the
  ultraviolet rays (UV) and the visible rays VIS) (ex: light energy).


Greenhouse gases absorb and reflect heat energy
"greenhouse effect"
     - is the heating of the Earth due to the presence of greenhouse gases
      - is the process by which absorption and emission of radiation by gases
       (called greehouse gases) in the atmosphere warm a planet’s lower
        atmosphere and surface.
                                               Short wavelength (UV and VIS) solar radiation
                                               from the sun passes through earth's
                                               atmosphere
                                               then is absorbed by the surface of
                                                the Earth, causing it to warm. Heat
                                                energy involves longer wavelength IR

                                               Part of the absorbed energy is then
                                               reradiated back to the atmosphere as
                                               long wave infrared radiation (heat).
                                               The greenhouse gases absorb these
                                                waves and reemits the waves
                                                in all directions including downward,
                                               causing the lower atmosphere to warm.
Greenhouse effect: Is it good or bad?
Good effect
  - It controls the temperature of the atmosphere. Without it, the world with not be
    livable
   - It protects the earth from sub zero environment

Bad effect

  -The overproduction of the so called greenhouse gases has made the geenhouse
  shield too thick, thus increasing the temperature of the earth to almost undesirable
  Temperature – causing global warming and extreme weathers
Most common greenhouse gases
   1. Carbon dioxide (CO2) and carbon monoxide (CO)
   2. Methane (CH4)
   3. Chloroflourocarbons (CFCs)
   4. Nitrous oxide (NO2)
                 Major Greenhouse Gas                    Formulas   Lifetime
                                                                    (years)
                 Carbon dioxide                          CO2
                 Methane                                 CH4        12
                 Ozone                                   O3
                 Other Gases of Anthropogenic Origins
                 Dinitrogen oxide                        N2O        114
                 chloroflourocarbons
                     CFC-12                              CCl2F2     100
                     HCFC-22                             CHClF2     12
                     tetraflouromethane                  CF4        50,000
                     hexaflouroethane                    C2H6       10,000
                  Sulphur hexaflouride                   SF6        3,200
                 Nitrogen triflouride                    NF3        740



- naturally occurring greenhouse gases have a mean warming effect of about 33 °C
 - over the past century, greenhouse gases and other air pollutants released into the
   atmosphere have been causing big changes like global warming, ozone holes, and acid
   rains Ex:
                          Gas       Preindustrial level Current level Increase since 1750

                      Carbon dioxide                    280 ppm                388 ppm    108 ppm

                          Methane                       700 ppb                1745 ppb   1045 ppb

                       Nitrous oxide                    270 ppb                314 ppb     44 ppb

                           CFC-12                          0                   533 ppt    533 ppt
Carbon dioxide, CO2




      - a colorless, odorless non-flammable gas
      - carbon Dioxide is emitted into the air as humans exhale, burn fossil fuels
        for energy, and deforest the planet.

         Cellular respiration: C6H12O6 + 6O2 → 6CO2 + 6H20

           Burning: Carbohydrate + O2 → CO2 + H2O
Methane, CH4




 - a colorless, odorless, flammable gas.

 - It stays in the atmosphere for only 10 years, but traps 20 times more heat
    than carbon dioxide.
- it is formed when plants decay and where there is very little air (swamp gas)
     production is hastened by the presence of methanogens - are bacteria
      that are commonly found in deteriorating plants in the absence of oxygen
     and in the gut of animals

- Burning of methane produces CO2 and H2O which are also greenhouse gases
         CH4 + 2O2 → CO2 + 2H2O
Halocarbons - hydrocarbons with halogen substituents, CFCs and the HFC
              Ex: dichlorodiflouromethane, CCl2F2
                   Chlorodiflouromethane, CHClF2
                    Tetraflouromethane, CF4

 - they have no natural sources but are entirely synthesized as refrigerants, aerosol
    propellants for fire retardants, and cleaning solvents

  - their production started in 1928 and since then there was an observed rise
    of CFCs in the atmosphere


  - uses of CFCs are now being controlled under the terms of the Montreal Protocol
  - they have long atmospheric lifetimes in the atmosphere.

       Ex: CCl2F2 ~ 100 years in the atmosphere
            CHClF2 ~ 12 years
               CF4 ~ 50,000 years
   - they also destroy the ozone layer
Nitrous oxide (N2O)




      - colorless greenhouse gas, however, it has a sweet odor
      - used as anaesthetic
     - (laughing gas)

 Sources:
  - released naturally from oceans and by bacteria in soils.
  - a by product of nitrogen based fertilizers
  - by product of gasoline decomposition by automobiles
 Other greenhouse gases
   - SF6 (sulfurhexafluoride) and NF3 or N2F6 (nitrogen triflouride)

 - They occur in very small amount but they are very potent greenhouse gases

 - They are gases with high global warming potential (GWP)
    GPW – a measure of how much heat is trapped by the gas

Note: Major atmospheric constituents, N2, O2, and Ar are not greenhouses

        - They do not absorb energy at IR wavelength

 Note: Carbon monoxide is not a greenhouse gas

       - can react with O2 to form CO2
        2CO + O2 → 2CO2
Water, H2O




- water vapor is a potent greenhouse gas owing to the presence of the hydroxyl
   bond which strongly absorbs energy in the infrared region
- the latent heat of vaporization, which is released to the atmosphere whenever
  condensation occurs contributes to further environmental heating
- “positive feedback loop” - a higher concentration of water vapor would be able to
                             absorb more thermal IR energy radiated from the Earth,
                              thus further warming the atmosphere.
        greenhouse water vapor reflects heat to the earth
        Earth atmosphere becomes hotter
        Higher temperature allows higher water evaporation from seas/oceans/rivers
         higher concentration of water vapor is then able to absorb more
         thermal IR energy, thus further warming the atmosphere.
         The warmer atmosphere can then hold more water vapor and so
            on and so on.
Causes of global warming or increase in greenhouse production

  1. Increasing population growth
     - garbage to decompose: decomposition leads to more CO2 production

  2. Increase in energy consumption ≈ increase in the release of CO2
                                       ≈ increase in the release of NO2
   3. Increase in the use of refrigerants using CFC gases.
       - after use, these gases stay in the atmosphere for a long time

   4. Increase in methane gas production.
       - Farts from cattle contain high percentage of methane gas
       - Methane gases from marshes, swamps, and rice paddy fields
       - Methane resulting from termite bites
Predictable effects of global warming if the amount of CO2 now present is doubled

1. Melting of the arctic and antarctic ice edges increasing the sea levels
     - Coastal areas or islands would be swamped and inundated
     - Areas already below sea levels would be flooded

  2. Faster evaporation of water would lead to dry lands getting drier
       - Rainfall pattern would be disrupted

       - There would be drastic changes in the existing climate

  3. Change in life patterns

       - Some plants and animals may cease to exist
        - Food supply would drastically be lessened
        - Inevitable population migration (great migration)


  What can you do to arrest global warming?
Acidic solution – one which contains an excess of the
                  hydrogen ion concentration
                    �������� ����
              H2O               H+ + OH-

pH - negative logarithm of the H+ concentration (-log H+)
   - a measure of the hydrogen ion concentration of a
       solution
pH = 7, neutral               pH < 7, acidic      pH > 7, basic

Distilled water – pH = 7
normal rain – slightly acidic
            - has a pH of below 7 but not lower than 5.7
                  CO2 + H2O           H + - + HCO2−
                                                 3
 Acid Rain
    - any form of wet (rain, snow, sleet, fog, cloudwater,
    dew) and dry (other particulates and gases) deposition
    from the atmosphere containing higher than normal
    amounts of nitric and sulfuric acids.
    - high H+
    - low pH, could go as low as 2.0
      average pH = 4.2
      l
Main Cause of Acid Rain
 - the large emission of sulfur dioxide (SO2) and
 nitrogen oxides (NOx) to the atmosphere
Emission of SO2
 - from volcanoes
 - a by-product in power plant generation where coal is used
 - combustion of fuels for motor vehicles
 - industries (like the pulp and paper industries) that
     produce as byproduct the volatile flammable liquid
     dimethyl sulfide
- product of phytoplankton metabolism

Emission of NOX
- from lightning: N2(g) + O2(g) �������������������������������� ���������������������������� 2NO(g
- by-product in power plant generation where coal is used
- combustion of fuels for motor vehicles
How acid rain is produced from SO2
 Step 1: SO2 + OH∙ → HOSO2∙
 Step 2: HOSO2∙ + O2 → HO2∙ + SO3
 Step 3: SO3 + H2O → H2SO4 → 2H+ + SO2−
                                     4

 How acid rain is produced from NOX
 With NO
 Step 1: NO + OH∙ → HNO2
                H2 O
 Step 2: HNO2          H+ + NO1−
                              2

 With NO2
 Step 1: NO2 + OH∙ → HNO3
                H2 O
 Step 2: HNO3          H+ + NO1−
                              3
Effects of Acid Rain
- acidification of lakes and bodies of water
   • pH of below 5 does not allow fish eggs to hatch
   • some fishes may not be able to tolerate low pH
   • corals which are mainly made up of limestone may be
         weakened
- acceleration of corrosion of metals
                  ���� +
      4Fe + 3O2
             ,           2Fe2O3
- soil biology and chemistry is changed
  • acids can make the metallic ions such as aluminum,
      calcium, and magnesium more soluble, removing them
      as food source of plants
  • microbial organisms may not be able to tolerate the
      high acidity
- forests and plants may be damaged
- dry precipitation (SO2 and NOX gases) contribute to lung
    diseases
      • asthma
      • bronchitis
       • coronary obstructive disease
       • skin allergies

- erosion of stone statues made mainly of limestone and
marble. CaCO3 (s) + H2SO4 (aq) CaSO4 (s) + CO2 (g) + H2O (l)
Natural resources -materials and components (something that can be used) that can be
                   found within the environment.
Ubiquitous resources - resources can be found everywhere such as sunlight and air

Inexhaustible resources - will not run out in foreseeable future
                        - Examples are: solar radiation, geothermal energy, and air
Biotic resources - obtained from the biosphere (living and organic material), such as
                 forests, animals, birds, and fish and the materials that can be obtained
                 from them.
                  - fossils such as coal and petroleum are also included in this category
                  because they are formed from decayed organic matter.

 Abiotic resources - those that come from non-living, non-organic material.
                   - Examples: land, water, air, heavy metals such as gold, iron, copper, etc.
Renewability of Natural Resources
1. Renewable - can be replenished naturally
            - Examples: sunlight, air, wind, etc., are continuously available and their
                        quantity is not noticeably affected by human consumption.

              - considered renewable only so long as the rate of replenishment/recovery
                exceeds that of the rate of consumption.


 2. Non renewable -    their rate of consumption exceeds the rate of replenishment/recovery
                      - examples: fossil fuels and mineral deposits are in this category
                      because their rate of formation is extremely slow (potentially millions
                      of years), which means they are considered non-renewable from a
                      human use perspective
Renewable Energy Resources
1. Solar energy - collected and converted by photovoltaic cells known as solar cells
2. Hydroelectric power - The kinetic energy in the falling and flowing of water in rivers and
                         streams is used to produce electricity
3. Energy from heat stored in water
     Ocean Thermal Energy Conversion (OTEC)
  Mechanics:
   1. Warm surface water is pumped through a heat exchanger and used to
      evaporate liquid ammonia.
   2. The ammonia gas (working fluid) is used to drive turbines that generate
      electric current
   3. The used gas in converted back to liquid ammonia by cold water from the
       deeper part of the ocean
OTEC facilities
Advantages of OTEC facilities
1. minimal environmental impacts - no greenhouse gas emissions
2. Produces desalinated water for industrial, agricultural, and residential uses
3. Provides air-conditioning for buildings
4. The cold, deep seawater used in the OTEC process is also rich in nutrients,
   and it can be used to culture both marine organisms and plant life

 Disadvantages
   1. Still not highly efficient
   2. Localized only in the tropics
4. Wind energy
   Wind - simply air in motion
         - caused by the uneven heating of the Earth's surface by the sun.
         - the Earth's surface is made of very different types of land and water,
           it absorbs the sun's heat at different rates.


     The Daily Wind Cycle

Sea Breeze—A coastal breeze blowing
from sea to land caused by the
temperature difference when the land
surface is warmer than the sea surface.
The sea breeze usually occurs during
the day.

Land Breeze—A coastal breeze flowing
from land to sea caused by the
temperature difference when the sea
surface is warmer than the adjacent
land. The land breeze usually occurs at
night
Wind - simply air in motion
     - caused by earth’s rotation
      -the equator is hotter than the north
        and south poles




                                              Coriolis force
                                              -force created by the rotation of the Earth
                                              - it deflects air to the right (east) in the
                                                 Northern Hemisphere
                                              - the effect is the northeast trade wind
                                               - at the lower hemisphere, the effect is
                                                called the southwest trade wind
Wind power- energy created and stored using the kinetic energy that comes
          naturally from the wind
            - the process of capturing that wind energy and converting it to
            electrical power that can be used in households across the nation.
             - wind power is captured using a wind electric turbine
Wind Turbines
   - With an average of 14 – 34 miles per hour, a small turbine can generate
     10-1000kilowatt of electricity
   - approximately 2.5% of electric consumption is generated by wind power
   -Competitive price - the overall cost per unit of energy produced is similar
    to the cost for new coal and natural gas installations
    - the fastest growing source of renewable energy today
   The world’s largest turbine which is in operation as of 2011 has an output of
   340 MW (built by Siemens’ Power Generation).
Advantages of wind power
   - produces no greenhouse gas emissions
    -represents a renewable source of energy, which decreases dependence
      on foreign fossil fuels

Disadvantages
    - may cover a large area of land
    - an increase of bird and wildlife mortality is observed closed to these windmills
    - noise pollution
    - uneven and unpredicted wind supply
Biomass
  - renewable energy from plants and animals

  - an organic plant material that can be burned directly as fuel or converted
    to gaseous or liquid biofuels through chemical processes such as distillation,
    pyrolysis, and esterifications
 - a renewable energy source because we can always grow more trees and
   crops, and waste will always exist.
 - examples of biomass fuels are wood, crops, manure, and some garbage.
  - when burned, the chemical energy in
    biomass is released as heat
       - to produce steam for making
         electricity, or to provide heat
         to industries and homes
Harnessing energy from biomass by conversion technologies such as
 1. Thermal conversion - burning, combustion, or pyrolysis

 2. Chemical conversion - transesterification
 3. Biochemical conversion - fermentation and composting
Combustion
   - wood waste or garbage can be burned to produce steam for making electricity,
     or to provide heat to industries and homes
   - the rapid oxidation of the feedstock producing energy. The energy is used to
     heat a boiler. High pressured steam is is produced to rotate a turbine which
     powers a generator.
   - Exothermic reaction: Organic material + O2 → CO2 + H2O + heat
Pyrolysis is a thermochemical decomposition of organic material at elevated
         temperatures without the participation of oxygen producing organic
         gases and oils.
Anaerobic digestion is a biological decomposition process where bacteria are
used in controlled anaerobic conditions to break down biodegradable organic
waste.




     The key by-product of anaerobic digestion is methane gas which is produced
     by the bacteria decomposing the organic waste and can be captured and
     utilised as a biogas.
Aerobic composting
  - similar to anaerobic digestion with
   the key difference being the presence
   of oxygen
  - the presence of oxygen means than
  different bacteria are employed

  - aerobic composting produces gases
  which can be captured and utilised for
  energy

  - raw organic materials (such as crop
  residues, animal wastes, food garbage,
  some municipal wastes and some
  industrial wastes) enhance their suitability
  as fertilizers after composting.
Fermentation
    - a biological process in which enzymes produced by microorganisms catalyze
      chemical reactions
     - these microorganisms digest sugars to produce the energy and chemicals
     they need for survival while giving off by-products such as carbon dioxide,
     organic acids, hydrogen, ethanol, and other products, which are then collected
     and utilized for energy production
 Biofuels - include fuels derived from biomass conversion, as well as solid biomass,
liquid fuels, and biogases
Examples: biomass – wood, paper, sawdust, etc

            liquid fuels – bioethanol derived from fermentation
                          - biodiesel derived from transesterification of fats
            biogases - methane derived from anaerobic decomposition of biomass

Bioethanol - the most widely used alternative automotive fuel in the world,
            - but pure ethanol (or bioethanol) can not be used for spark-ignition
              engines due to its low vapour pressure and high latent heat of
              vaporization which make cold start problematic
            - blends used to increase functionality of bioethanol
               •E5G to E26G (5-26% ethanol, 95-74% gasoline)
               •E85G (85% ethanol, 15% gasoline)
               •E15D (15% ethanol, 85% diesel)
               •E95D (95% ethanol, 5% water, with ignition improver)
           - worldwide, most bioethanol is produced from sugar cane, molasses
             and corn, but other starchy materials such as wheat, barley and rye are
              also suitable
            - a feedstock of around 3 tons of grains is needed for the production of
              1 ton of ethanol.
Biodiesel is an alternative fuel similar to conventional or ‘fossil’ diesel, which is used
to ignite diesel engines
  Transesterification - the process of converting a fatty acid to biodiesel




  *11% of world’s energy was biofuel in 1984

  *15% by the 1st decade of the 21st century
Non-renewable Energy Resources
 1. coal, petroleum, and natural gas
 2. Geothermal resources
 3. Nuclear power
Coal - Coal is a combustible, sedimentary, organic rock, which is
       composed mainly of carbon, hydrogen and oxygen.
     - formed from decayed plants, pressed between fossilized by the
        combined effects of pressure and heat over millions of years.
     - around 100 years of coal remaining worldwide.

 Coalification - geological process of forming materials of high
 carbon content from decayed organic materials followed by a
 gradual transformation into coal by action of moderate
 temperature (about 500 K) and high pressure in a geochemical
 stages.
Peat - the precursor of coal. It is formed by the action of bacteria on plant debris.


Coke – carbonized coal

      - the carbon content is increased by changing the hydrocarbons to carbon

       and removing the moisture content of coal.

     - CnH2n+2 + O2 → C + H2O


Tar - a brown or black liquid of extremely high viscosity.

    - a by-product when coal is carbonized to make coke or gasified to make coal

     gas.

   - a mixtures of phenols, polycyclic aromatic hydrocarbons (PAHs),

     and heterocyclic compounds, about 200 substances in all.
                     Types of Coal
1. Lignite
 - The softest and the lowest in rank of the
 four types of coal.
 -Yellow to dark brown or rarely black.
 - Contains about 25%-35% carbon (on a dry,
 ash-free basis) and has a calorific value near 17
 megajoules per kilogram (7,000 BTU per pound).

 2. Subbituminous
 -Intermediate in rank between lignite and
 bituminous coal.
 -Dark brown to black coal.
 -It contains 42%-52% carbon (on a dry, ash-free
 basis) and has calorific values ranging from
 about 19 to 26 megajoules per kilogram (about
 8,200 to 11,200 BTU per pound). It is
 characterized by greater compaction than
 lignites as well as greater brightness and luster.
3. Bituminous
-Most abundant form of coal.
-Intermediate in rank between subbituminous
coal and anthracite.
-The carbon content of around 60%-80%.
-Calorific values of 24 to 35 megajoules per kg
(10,500-15,000 BTU per pound)

4. Anthracite
-The most highly metamorphosed and highest
in rank of coal.
-It contains fixed carbon of about 86%-98% on
a dry, ash-free basis.
-Has calorific values near 35 megajoules per
kilogram
-Anthracite is the least plentiful form of coal.
Petroleum - a yellow-to-black liquid with a pungent odor made up
          of a mixture of hydrocarbons and other organic materials
          that are found beneath the surface of the earth.
           - also called crude oil
          - a fossilized liquid

          - The main component is the hydrocarbon family
             paraffins, aromatics, naphtenes, alkenes,
                  dienes and alkynes
           Ex: methane, CH4
               Propane, C3H8
               Butane, C4H10

              Octane, C8H18
Components of petroleum are separated in oil refineries
 Coal and petroleum are used as a fuel to generate electricity
 by combustion
   - It is burned in a furnace to convert water to steam. The energy
     of the steam is used to to spin turbines which turn generators
     that create electricity.
      Combustion: C(s) + O2(g)  CO2(g) + heat
                    CnH2n+2 → CO2 + H2 O + heat



- Disadvantages of Coal and Petroleum as Power Sources:
 1. The by products of combustion are: sulfur dioxide,
    carbon dioxide and nitroxide.
         - NO2 and SO2 contribute to acid rain
         - CO2 is a greenhouse gas
     2. Non-renewable source of energy
    Natural Gas
• “fuel of the future”
• found deep underground, or extracted through driven wells.
• formed beneath the earth’s surface by the decomposition of organic matter
• 85-90% methane, with varying amounts of ethane, propane, butane, and
  other hydrocarbon compounds.
• In its natural state, the gas is colorless, odorless, and lighter than air.

Extraction
• Natural gas is formed along with oil fields and coal beds
• It can also be obtained from coal through coal gasification.
• Natural gas is often referred to as the cleanest alternative burning fossil fuel.
   It can be used in the form of compressed natural gas (CNG) or liquefied
   petroleum gas (LPG).
Advantages
• Is more environment friendly than oil or coal. For same amount of
  heat, natural gas emit 30% less carbon dioxide than burning oil and
  45% less carbon dioxide than burning coal.
• Due to clean burning process, doesn’t produce ashes after energy
  release.
• Is cheap (less expensive than gasoline) therefore, very cost effective.
• Can be safely stored and burned.


Disadvantages
• Is highly volatile (highly flammable) and can be dangerous.
• Is colorless, odorless and tasteless.
• The most common cause of carbon monoxide deaths.
• Constructing and managing such pipelines cost a lot.
 nonrenewable energy resource. It’s availability is finite. Critics also
   point that their extraction leaves out large craters within the earth.
  The Malampaya Project: The Philippine Natural Gas Source
•one of the largest and most significant industrial endeavors in Philippine history.
• the project is spearheaded by the Philippine Department of Energy (DOE)
 developed and operated by Shell Philippines Exploration B.V. (SPEX)
•to extract natural gas and condensate from the sea floor.
 >>sub-sea facilities, a shallow water production platform, an underwater
 pipeline, a catenary-anchored leg mooring buoy, and an onshore processing gas
 plant.
•In 1989, a small gas reservoir called Camago was discovered.
•In 1992, SPEX discovered the Malampaya gas field, and was later found to be
 connected to the Camago structure.
•In 1998, former President Fidel V. Ramos signed the declaration of commerciality
 of the venture.
•In October 2001, the Malampaya Deep Water Gas-to-Power Project was
 inaugurated in a special ceremony at the onshore gas plant in Batangas.
                             Environmental Concerns

•   How to control the use of the natural resources

•   How to rehabilitate the area after operations

•   How to provide a proper and formal mechanism for sustainable development

•   Maintain health and safety of the environment and people
Nuclear reactions
     - reactions involving the nuclei of atoms
     - these reactions occur with a simultaneous release of heat and radiations
     - nuclear reactions maybe naturally occuring or induced
Types of radiations
Types of Nuclear Reactions
 1. Nuclear fusion – two or more small nuclei fuse together to form a bigger nucleus
                     accompanied by a release of massive heat and radiation
    examples




 2. Nuclear fission - a nuclear reaction in which a heavy nucleus splits spontaneously
                      or on impact with another particle, with the release of energy
    examples
Nuclear power
   - an energy which is produced with the use of a controlled nuclear reaction
Nuclear power plant – a thermal energy source in which heat is generated from
                      nuclear reactors
                    - as of Jan. 2013, there is a total of 439 nuclear power
                       reactors world wide.
Advantages of Nuclear Power
- Environmental friendly because no CO2 and other greenhouse gases produced
 - More economical – more energy is produced from a lesser amount o fuel
                     - price of fuel is competitive with other fuel sources

  - Fuel source (Uranium) is still very abundant and “inexhaustible”


 Disadvantages
  - Fuel source is radioactive
     Uranium radiation may cause cancer
  - Fuel source is a heavy metal
    Ingestion of uranium metal may cause kidney failure

 - Proper disposal of fuel wastes should be observed
 - Possibility of power plant meltdown
- Security measures may be very expensive

				
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