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Chapter One

Chapter One. The Air We Breathe. What is in the air that we breathe?. Can air be dangerous to our health?. How can understanding chemistry help us decide?. Catatan: Diambil dari berbagai sumber. Where are we leaving ?. The Composition of Our Air in Troposphere.

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Chapter One

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  1. Chapter One The Air We Breathe What is in the air that we breathe? Can air be dangerous to our health? How can understanding chemistry help us decide? Catatan: Diambil dari berbagai sumber

  2. Where are we leaving ?

  3. The Composition of Our Air in Troposphere It’s a mixture – a physical combination of two or more substances present in variable amounts. 1.2

  4. Air Composition Nitrogen; N2; 78 %; Oxygen; O2; 21 % Argon; Ar; 0.9 %; Other Gases; 0.1 % O2 Ar N2

  5. Composition of the other gasses

  6. One Breath has 2.0 X 1022 molecules20 000 000 000 000 000 000 000 How many N2 molecules Are in a breath of air?

  7. Ozone (O3) If one breath of air contains 2 x 1022 molecules and atoms, and the acceptable ozone level is 0.12 ppm, how many molecules of O3 are in each breath? 0.12 O3 molecules 2 x 1022 molecules and atoms in a breath of air x 1 x 106 molecules and atoms in air = 2 x 1015 O3 molecules in a breath How many oxygen atoms are in each breath? 3 O atoms___ = 6 x 1015 O atoms 2 x 1015 O3 molecules x 1 O3 molecules 1.12

  8. When people breathe What’s in a Breath? Typical Composition of Inhaled and Exhaled Air

  9. Concentration Terms Parts per hundred (percent) Parts per million (ppm) Parts per billion (ppb) Atmosphere is 21% oxygen = 21 oxygen molecules per 100 molecules of air Midday ozone levels reach about 0.4 ppm = 0.4 ozone molecules 1 x 106 molecules of air Sulfur dioxide in the air should not exceed 30 ppb = 30 sulfur dioxide molecules1 x109 molecules of air 1.2

  10. 21% means 21 parts per hundred means 210 parts per thousand means 2,100 parts per ten thousand means 21,000 parts per hundred thousand means 210,000 parts per million The difference between pph and ppm is a factor of 10,000 Try Chapter 1 Figures Alive! for practice 1.2

  11. Classifying Matter All Matter NO YES Can it be separated by a physical process? Pure Substances Mixtures Can it be broken down into simpler ones by chemical means? NO YES Elements Compounds 1.6

  12. Three States of Matter Matter - anything that occupies space and has mass. 1.5

  13. Classifying Matter Classify each of these as an element, a compound, or a mixture: carbon dioxide nickel cocaine water compound element element fluorine table salt soap sea water compound compound compound mixture mixture 1.6

  14. The Periodic Table Group Period

  15. A space filling model for a water molecule, H2O Oxygen atom A moleculeis a combination of a fixed number of atoms held together in a certain spatial arrangement. The chemical formula symbolically represents the type and number of each element present. Two hydrogen atoms 1.7

  16. Many nonmetals occur as diatomic (made up of two atoms) molecules Cl2 O2 H2 N2 1.7

  17. Naming Binary Compounds 1. Name the more metallic element first, followed by the name of the less metallic element, modified with the suffix “ide” KBr postassium bromide BeO beryllium oxide ZnS zinc sulfide 1.8

  18. Naming Binary Compounds 2. Prefixes are used to designate the number of each type of element: number of atomsprefix 1 mono 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa 9 nona 10 deca 1.8

  19. Chemical Equations Reactant(s) -> Product(s) Carbon + Oxygen -> Carbon Dioxide C (s) + O2 (g) -> CO2 (g) • Reactant bonds are broken; Product bonds are made • Same number and type of atoms on both sides of equation

  20. Chemical reactions are characterized by the rearrangement of atoms when reactants are transformed into products This is an example of a combustion reaction C + O2 CO reactants product But the number of atoms on each side of the arrow must be equal (Law of Conservation of Mass) 2 C + O2 2 CO (balanced) 2 carbon atoms two carbon atoms 2 oxygen atoms two oxygen atoms 1.9

  21. 2 C + O2 2 CO + 1.9

  22. Balancing equations: • if an element is present in just one compound on each side, balance it first • balance anything that exists as a free element last • balance polyatomic ions as a unit • check when done – same number of atoms, and same total charge on both sides C3H8 + O2 CO2 + H2O C3H8 + 5 O2 3 CO2 + 4 H2O 3 C atoms 8 H atoms 10 O atoms 3 C atoms 8 H atoms 10 O atoms 1.9

  23. Direct Source of Sulfur Trioxide Coal + O2 SO2 (1-3% sulfur) 2 SO2 + O2 2 SO3 Good News: Since 1985 we have seen a 25% reduction in SO2 emissions in the U.S. 1.11

  24. Direct Source of Nitrogen Oxides High temperatures from auto engine or coal-fired power plant N2 + O2 + high temp 2 NO (nitrogen oxide) Simplified version of chemistry that occurs NO is very reactive: 2 NO + O2 2 NO2 1.11

  25. Properties of the troposphere Atmospheric pressure changes with altitude temperature changes In Troposphere : Altitude increases  P and T decrease In Thermosphere : Altitude increases  P decrease, T increases

  26. Quality of The Air • Air Quality Index(AQI) : USA • Air Pollution Index(API) : Hong Kong, China, Malaysia • Indeks Standar Pencamaran Udara (ISPU) : (Air Pollution Standard Index /APSI) Indonesia

  27. Air Quality standards How are standards established? Through risk assessment --consider the toxicity of the compound and the exposure. Toxicity: How dangerous a compound is. Exposure: Refers to the length of contact with the pollutant and the concentration of the pollutant

  28. EPA’s Air Quality Index 1.3

  29. Indonesian Air Quality Index (indeks standar pencemaran udara =ISPU) • Pollutant parameters : • Carbon monoksida (CO) • Nitrogen (NO2) • Ozone (O3) • Sulfur dioxide (SO2) • Particulate Matter (PM10)

  30. Hubungan ISPU dan kondisi lingkungan

  31. API- Malaysia 0-50  Good 51-100 Moderate 101-200 Unhealthy 201-300 Very unhealthy 301- Hazardous

  32. Air Pollution • Air pollutants are airborne particles and gasses that occur in concentrations that endanger the health and well-being of organisms or disrupt the orderly functioning of the environment. • Pollutants can be grouped into two categories: • (1) primary pollutants, which are emitted directly from identifiable sources, and • (2) secondary pollutants, which are produced in the atmosphere when certain chemical reactions take place among primary pollutants.

  33. Primary Pollutants The major primary pollutants include: • particulate matter (PM), • sulfur dioxide, • nitrogen oxides, • volatile organic compounds (VOCs), • carbon monoxide, and • lead.

  34. Secondary Pollutants • Atmospheric sulfuric acid is one example of a secondary pollutant. • Air pollution in urban and industrial areas is often called smog. • Photochemical smog, a noxious mixture of gases and particles, is produced when strong sunlight triggers photochemical reactions in the atmosphere. • The major component of photochemical smog is ozone. • Although considerable progress has been made in controlling air pollution, the quality of the air we breathe remains a serious public health problem.

  35. Major Sources of Air Pollutants Combustion of coal in coal burning power plants Coal is mostly Carbon; The main impurity in coal is sulfur, S. Combustion of fuel in car, trucks, and other vehicles.

  36. Sulfur Oxides, SOxSO2, SO3 S + O2 SO2 When coal is burned, so is the Sulfur impurity

  37. The SO2 then burns to produce SO3. 2 SO2 + 1 O2 2 SO3

  38. SO3 gas then dissolve in water to make a component of acid rain, H2SO4 (aq). H2SO4 (aq) SO3 (g) + H2O (l) In general; nonmetal oxides dissolve in water to make it acidic

  39. Problems with SOx SOx are respiratory irritants SOx dissolve in water to make a component of acid rain.

  40. Scrubber

  41. Carbon Monoxide, CO COMPLETE COMBUSTION CxHy (l) + O2 (g) -> CO2 (g) + H2O (g) INCOMPLETE COMBUSTION CxHy (l) + O2 (g) -> CO (g) + H2O (g) +VOC (g)

  42. Carbon Monoxide, CO

  43. Reducing CO Emissions Post Combustion Change/Replace Combustion Process Pre-Combustion

  44. Catalytic Converter Principles of Environmental Chemistry; by James E Girard;Jones and Bartlett Publisher, Inc; 2005, pg121

  45. Catalytic converters are used to catalyze the conversion of CO to CO2 The converters also reduce the amount of Volatile Organic Compounds (VOCs) from tailpipe exhaust 1.11

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