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Unit C Environmental Chemistry

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Unit C Environmental Chemistry reference p 183 - 190 Science in Action 9 NUTRIENT UPTAKE IN DIFFERENT ENVIRONMENTS Where an organism lives affects how it takes up ... – PowerPoint PPT presentation

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Title: Unit C Environmental Chemistry


1
Unit C Environmental Chemistry
  • reference
  • p 183 - 190 Science in Action 9

2
What is Environmental Chemistry
  • Environmental Chemistry Summary
  • Should you trust Chemists or Cows?

3
UNIT C ENVIRONMENTAL CHEMISTRY   Section
1.1 Chemicals in the Environment
  • All living things are made of chemicals and
    depend upon chemistry for survival.
  • Some chemicals that are produced either
    naturally or by humans can be harmful to the
    living and non-living environment.
  • Elements such as carbon and oxygen are
    constantly moving throughout the ecosystem in a
    cyclic pattern as they form chemical compounds
    that are used by living things.
  • Water is a compound that cycles through the
    environment.

4
  • The Nitrogen Cycle
  • Nitrogen is an important element since it is
    required by plants to make substances necessary
    to life.

5
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6
  • The concentration of useable nitrogen can be
    added or taken away from the soil in several
    ways 
  • Nitrated are added by
  • 1. nitrogen fixing plants
  • 2.fertilizers/compost/manure
  • 3. lightning
  • Nitrates are taken away by
  • 1. bacteria that convert soil nitrates into free
    N2
  • 2. water carries away nitrates
  • 3. harvesting plants

7
More on nitrogen fixation
  • Nitrogen fixing plants like legumes (clover,
    alfalfa, beans) contain bacteria in their root
    nodules
  • These bacteria convert free nitrogen (N2) in the
    air into nitrates that can be used by plants, so
    they fertilize the soil!
  • Nitrogen and Phosphorus cycles

8
  • Processes and Activities that Affect
    Environmental Chemicals
  •  
  • A. Natural Processes
  • Chemical Cycles cycling of elements and
    compounds through the environment, like the
    nitrogen cycle
  • Cellular respiration food chemicals and oxygen
    are used to provide the body with energy, carbon
    dioxide is produced

9
  • B. Human Activities
  • 1. Pollution any change in the environment that
    produces conditions harmful to living things,
    such as smog and forest fires

10
There are many kinds of pollution
  • Noise
  • Thermal (Lake Wabamun)
  • Chemical

11
The Effects of Pollution
12
  • 2. Agricultural Activities farmers use
    chemicals to help control the growth of their
    crops.
  • a) Fertilizers - chemicals added to the soil to
    increase plant growth.
  • - usually contain nitrogen, phosphorus and
    potassium, three elements essential for plant
    growth. Sometimes sulfur is added.

13
10 K
  • Fertilizers are labeled with a number that
    indicates the percentage of nitrogen, phosphorus
    and potassium
  • Different ratios are used to achieve different
    goals
  • Eg. Root growth, or leaf growth

problem too much can harm the crop
14
  • b) Crop rotation
  • Crops that are nitrogen fixing increase soil
    nitrates
  • eg. clover, alfalfa and peas

15
  • c) Pesticides - chemicals used to kill pests
    (organisms that harm people, crops or
    structures).
  • - grouped by what they kill herbicides kill
    weeds,
  • insecticides kill insects, fungicides kill fungus

16
  • Problems
  • 1. some are not selective and kill both pests
    and non-pests (Round-up)
  • 2. some remain in the environment and can be
    passed on to other organisms
  • 3. pests can become resistant to them

17
  • Organic Foods- are grown in an environment free
    of pesticides

18
PESKY PESTICIDES
  • an estimated 20,000 cancer deaths each year in
    the U.S. are caused by pesticide residues on food
  • an estimated 3.5 million cases of acute pesticide
    poisoning are caused each year in developing
    nations due to lack of protection during
    pesticide application
  • an estimated 900 plant and insect species have
    built up resistances to pesticides

19
  • 4.1 billion pounds of pesticides are used
    throughout the world each year
  • 30 times more pesticides are used today than were
    used in 1945
  • 30 percent of insecticides are believed to be
    carcinogenic
  • 60 percent of herbicides are believed to cause
    cancer
  • 90 percent of fungicides are believed to be
    carcinogenic (cause cancer )
  • 23 of the 28 most commonly used pesticides are
    believed to be carcinogenic

20
  • 3. Solid Wastes garbage from homes and industry
    that cannot be recycled is put into landfills
    which are specially constructed with plastic
    liners and compacted clay to prevent chemicals
    leaking into the ground (leaching).
  • Some solid waste is incinerated or burned at high
    temperatures and some of the gases released
    contribute to air pollution.

21
4. Wastewater or Sewage water containing
dissolved and undissolved materials, called
sewage, is carried by pipes into a septic tank in
rural areas and to water treatment plants in the
city. Septic tank underground container where
bacteria break down organic materials before they
are moved out into the soil Sewage treatment
plant treats wastewater from homes and industry
and releases it (now called effluent) into rivers
and lakes. Effluent often contains nitrogen and
phosphorus.
22
  • Storm sewers large areas used to collect
    street water before it is released into rivers
    and lakes. This water contains chemicals washed
    off the street.

23
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24
Waste Water
Sewage (all waste water from your home) enters
here!
25
  • 5. Fuel combustion oxygen is used to burn
    fossil fuels and energy, H2O (g), CO2 (g), are
    released.
  • Fossil fuels fuels formed from dead plants and
    animals, such as coal, oil and natural gas.
  • - these are also called hydrocarbons since they
    are made up of hydrogen and carbon though they
    may contain oxygen, nitrogen and sulfur
  • - when burned, these fuels often release
    pollutants such as sulfur dioxide, nitrogen
    oxides and traces of mercury and lead

26
  • 6. Industrial Processes including electrical
    power generation, mineral processing and
    fertilizer production 

27
  • Natural gas natural gas is composed of various
    compounds that can be separated and used.
    Methane, propane and butane are used for heating
    and ethane is used to make plastics.
  • An unwanted substance is the poisonous chemical
    hydrogen sulfide. If gas contains this chemical,
    it is called sour. To remove it, sulfur and
    sulfur dioxide are made. Since sulfur dioxide is
    a pollutant, there are restrictions on the amount
    released.
  • The sulfur is recovered and used to make
    fertilizers, paints and steel.

28
What can YOU DO?
  • Use phosphate free laundry detergent
  • biological controls instead of pesticides
  • walk or ride your bike instead of consuming
    fossil fuels and creating pollution
  • reduce your solid wastes

29
  • P 181 Quicklab

30
  • Do questions 1-11 on page 190

31
Topic 1.2
  • ACIDS AND BASES

32
The pH Scale
  • pH is a measure of the concentration of hydrogen
    ions in solution
  • 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
  • Most Acidic 7 neutral Most
    Basic

33
  • pH is a base 10 logarithmic scale.
  • Every increment is a power of 10.
  • A pH of 5 is 10 times more acidic than a pH of 6
    and 100 times more acidic than a pH of 7!
  • A pH of 12 is 10 times more basic than a pH of
    11.

34
ACIDS
  • taste sour
  • soluble in water
  • corrosive
  • conduct electricity
  • react with metals
  • most formulas begin with H (hydrogen)
  • Examples HCl - hydrochloric acid
  • H2SO4 - sulfuric acid
  • acids you would find at home include
  • acetic acid (vinegar) and citric acid (found
    in fruits)

35
  • Acid a compound that dissolves in water to form
    a solution with a pH lower than 7
  • acid rain is produced when chemical released from
    industrial processes combine with water to form
    acids that fall with the rain,
  • SO2 H2O? H2SO3 sulfurous acid,
  • Nox H2O ? HNO2 and HNO3

  • nitrous and nitric acid,
  • CO2? carbonic acid

36
Acid Rain
  • When gases in the atmosphere combine with water
    to form rain that is more acid than normal.
  • Kills and deforms living organisms, causes
    amphibian eggs not to hatch, increases rate of
    rust formation, chemical degradation of limestone
    statues and buildings.
  • Coal Combustion Acid Rain
  • BBC Acid Rain
  • Buffers - The slayes of Acid Rain

37

BASES
  • Taste bitter
  • soluble in water
  • feel slippery
  • corrosive
  • conduct electricity
  • react with acids
  • found in soaps, detergents
  • end in OH (Hydroxide )
  • Eg. NaOH - sodium hydroxide, fish oils

38
  • Base a compound that dissolves in water to form
    a solution with a pH higher than 7
  • - many household cleaners are basic, from Draino
    to shampoo and soaps

39
  • Neutral a pH of 7, it is neither acidic nor
    basic
  • e.g. Distilled Water
  • Acids can be neutralized by adding a base
    (liming), and bases can be neutralized by adding
    an acid.

40
  • Neutralization a reaction where an acid and
    base come together to produce water and a salt.
    This reaction can be used to neutralize stomach
    acid or basic chemical spills, and can help
    combat the effects of acid rain.
  • In some parts of Canada, rain can have a pH as
    low as 3. Acid rain can have devastating effects
    on the biotic and abiotic parts of the ecosystem.
  • One way to decrease its effect is to neutralize
    lakes by adding lime (calcium hydroxide),
    producing water with a neutral pH.

41
Neutralization Reaction
  • A reaction between an acid and a base where water
    (HOH) and salt are formed
  • E.g. HCl NaOH HOH NaCl
  • hydrochloric acid Sodium Hydroxide
    water sodium chloride (salt)

42
Buffers
  • A buffer is a substance that can neutralize
    either an acid or a base
  • An example of some bases which can buffer acids
    are antacids eno, tums, pepto bismol.
  • Baking soda is basic and can also buffer an acid.

43
  • Measuring pH
  • 1. pH meter the probe is dipped into a solution
    and the meter indicates the solutions pH
  • 2. pH indicators substances which change in
    color to indicate pH
  • ie. litmus paper blue litmus turns red in acid,
    red litmus turns blue in base
  • - pH paper is more accurate

44
  • a universal indicator shows a wide variety of
    colors, each indicating a different pH when
    compared to a color chart (They are a different
    color in an acid than in a base)
  • There are many other natural indicators
  • e.g. red cabbage

45
  • Lab measuring acids and bases
  • Bromothymol Blue
  • With acid-yellow
  • With base- blue
  • In neutral-green

46
  • Lab Neutralizing Acids p.194
  • 5 Human Impacts on the Environment

47
Unit C Section 1.3 Common Substances Essential
to Living Things
48
  • Of the 25 elements are needed for growth of
    living things, carbon, oxygen and hydrogen are
    the most common.
  • They make up molecules of carbohydrates, lipids,
    proteins and nucleic acids.
  • molecules that contain carbon are organic
  • those without carbon are called inorganic

49
  • Nutrients
  • elements and compounds needed for living,
    growing and reproducing
  • Macronutrients
  • 9 elements that are needed in large amounts.
  • C, H, O, N, P, K, Mg, Ca, S.
  • Micronutrients
  • elements needed only in trace amounts
  • Eg. Fe, Se

50
Nutrient Importance in Plants Importance in Humans
Nitrogen (N) - proteins chlorophyll - leaf and stem growth - composition of proteins nucleic acids - growth and repair of tissue
Phosphorus (P) - root and flower growth - cellular respiration photosynthesis - composition of bones, teeth DNA - metabolic reactions
Potassium (K) - stimulates early growth - starch and protein production - disease resistance - chlorophyll production tuber formation - muscle contraction nerve impulses
Magnesium (Mg) - chlorophyll structure - photosynthesis - composition of bones teeth - absorption of calcium potassium
Calcium (Ca) - cell wall structure - cell division - composition of bones teeth - blood clotting - muscle nerve function
Sulfur (S) - production of fruits and grains - protein synthesis - enzyme activation - detoxification
51
  • Optimum Amounts
  • too much or too little of a nutrient can be
    harmful to an organism.
  • eg. Selenium is an element required in trace
    amounts in our diet too little is linked to
    cancer and heart disease, too much can lead to
    death.

52
Types of Organic Molecules
  • 1. Carbohydrates
  • made up of C, H and O.
  • Foods like pasta, rice and potatoes are rich in
    complex carbohydrates.
  • There are two categories of carbohydrates

53
  • Simple Sugars
  • -one or two subunits long
  • -glucose is a simple sugar made by
    photosynthesis
  • Complex Carbohydrates
  • - long repeating chains of glucose joined
    together
  • - eg. starch, cellulose and glycogen.

54
  • Starch used for energy storage in plants
  • Glycogen used for energy storage in animals
  • Cellulose (fibre) found in plant cell walls

55
  • 2. Lipids
  • made up of many C, H and O atoms.
  • fats, oils or waxes
  • produced by both plants and animals.

56
  • 3. Proteins C, H, O, N
  • meats, fish, eggs and dairy all contain protein.
  • used for growth and repair and as a source of
    energy.
  • Enzymes are specialized proteins that control the
    rate of chemical reactions in the body.
  • Proteins are made up of repeating units of amino
    acids
  • There are 20 different kinds of amino acids.
  • Each protein has its own number and arrangement
    of amino acids

57
  • Proteins are long chains of amino acids

58
  • 4. Nucleic Acids C, H, O, N, P
  • largest and most complex molecules in living
    things.
  • play a major role in heredity and controlling
    cell activities.
  • Two nucleic acids are DNA (deoxyribonucleic acid)
    and RNA (ribonucleic acid)
  • They are made of a phosphate, a simple sugar, and
    a nitrogenous base.

59
Unit C Section 1.4 How Organisms Take in
Substances
60
Nutrients
  • Animals
  • Plants
  • Consumers rely on organic compounds made by
    plants for their energy, growth and repair.
  • Plants rely on inorganic compounds which they
    turn into organic compounds.

61
  • PLANTS
  • 1.Passive Transportation
  • movement of molecules that does not require an
    input of energy

62
  • a) Diffusion the natural movement of molecules
    from an area of high concentration to an area of
    low concentration. Nutrients move into plant
    roots this way until the concentration on the
    outside is equal to the concentration on the
    inside.
  • Diffusion Animation

63
  • b) Osmosis the movement of water molecules
    across a membrane due to a concentration gradient
    (from high to low concentration). Water moves
    into plant roots this way.
  • osmosis vs diffusion

osmosis demo with an egg
64
  • 2. Active Transport
  • energy is used to move molecules against the
    concentration gradient, from low to high
    concentration.
  • Roots of plants take up some nutrients this way.

active and passive transport
65
  • ANIMALS
  • 1. Ingestion
  • taking food into the body. Animals ingest, then
    breakdown the food particles for absorption.
  • 2. Mechanical breakdown
  • the physical breakdown of food by chewing.
  • 3. Chemical breakdown
  • enzymes breakdown food into its smallest
    particles through a process called hydrolysis.
  • This happens in the mouth, stomach and intestine.
  • Hydrolysis
  • the addition of water breaks down large food
    particles into its smallest form. These
    molecules have been hydrolyzed.
  • Nutrients are transported through the body by the
    bloodstream.

66
  • NUTRIENT UPTAKE IN DIFFERENT ENVIRONMENTS
  • Where an organism lives affects how it takes up
    nutrients.
  • Substrate the material on which an organism
    lives. Some organisms simply attach themselves
    to the substrate, but others actually feed off
    their substrate.

67
  • Assignment
  • Page 209 1 to 7
  • and page 211 1 to 9
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