Chemistry of the Environment

• What is the result of Cobalt (II) chloride paper in the presence of water?

  Color changes from blue to pink in the presence of water
• Copper (II) sulfate


  Color changes from white to blue in presence of water
• Purity of Water Test

  Can be tested by checking the melting and boiling points
• Pure substances melt & boil at specific and sharp temperatures
• Water boils at 100ºC & melts at 0ºC
• Distilled Water

  • Water that has been heated to form a vapor, & then condensed back to a liquid
  • Has very few impurities
  • Used in practicals
• Tap water contains more impurities thus it could interfere with the reaction
• Substances in water from Natural Resources

  • Dissolved oxygen
  • Metal compounds
  • Plastics
  • Sewage
  • Harmful microbes
  • Nitrates
  • Phosphates
• Sources of substances in water

  • Naturally occurring
  • Direct result of human activity
• Beneficial Substances

  • Dissolved oxygen
  • Metal compounds (essential materials for life)
  • Calcium & Magnesium
• Harmful Substances

  • Metal compounds (some are toxic like lead, arsenic & mercury)
  • Some plastics
  • Sewage
  • Nitrate & Phosphates
• Water Treatment

  1. Water is pumped into a sedimentation tank where it sits for a few hours

  2. Mud, sand & other particles fall to the bottom

  3. Water is then filtered

  4. Water can also be passed through carbon (in the form of charcoal) to remove tastes & odors

  5. Chlorination removes small microorganisms
• Fertilizer Components

  • Nitrogen
  • Potassium
  • Phosphorus
• Fertilizer Benefits

  • Makes chlorophyll
  • Makes protein
  • Promotes healthy leaves
  • Promotes growth
  • Promotes healthy fruit & flowers
  • Promotes healthy roots
• Soluble Fertilizer Compounds

  • Ammonium Nitrate
  • Ammonium Phosphate
  • Potassium Sulfate
• The most effective fertilizer has a compound or combination of compounds made mostly of nitrogen, phosphorous & potassium
• Composition of Air

  • 21% Oxygen
  • 78% Nitrogen
  • 0.9% Argon
  • 0.04% Carbon Dioxide
• Uses of Noble Gases

  • Helium fills balloons
  • Argon is used in tungsten lightbulbs
  • Krypton is used in lasers for eye surgery
• Uses of Oxygen and Nitrogen

  • Oxygen is used for steel making, welding, breathing apparatus
  • Nitrogen is used for food packaging, production of ammonia, production of silicon chips
• Investigating percentage of Oxygen in Air

  1. Pass a known quantity of air over metal

  2. Oxygen will react with the metal, forming a metal oxide

  3. The volume of the air without oxygen is measured using another gas syringe

  4. The metal will be heated
• Air Pollutants

  • Carbon Dioxide
  • Carbon Monoxide
  • Particulates
  • Oxides of Nitrogen
  • Sulfur Dioxide
• Carbon Dioxide

  • Complete combustion of carbon-containing fuels
  • Adverse Effects: Increases Global Warming, Leading to Climate Change
• Carbon Monoxide

  • Sources: Incomplete combustion of carbon-containing fuels
  • Adverse Effects: Toxic, combines with hemoglobin preventing oxygen supply to the body, Respiratory problems, Cancer
• Particulates

  • Sources: Incomplete combustion of carbon-containing fuels
  • Adverse Effects: Respiratory problems, Cancer
• Oxides of Nitrogen

  • Sources: Reaction of Nitrogen with oxygen in high temperatures
  • Adverse Effects: Produces photochemical smog, Dissolves in rain to form Acid Rain, Causing corrosion to metal structures, buildings & statures made of carbonate rocks, Damage to aquatic organisms, Pollutes crops & water supply, Irritates lungs, throats & eyes, Respiratory problems
• Sulfur Dioxide

  • Sources: Combustion of fossil fuels donating sulfur compounds, Power stations are a major source
  • Adverse Effects: Dissolves in rain to form Acid Rain, Has similar effects as the acid rain caused by oxides of nitrogen
• Greenhouse Effect

  1. The Sun emits energy as radiation, which enters the Earth's atmosphere

  2. Some thermal energy is reflected & the energy passes through the atmosphere

  3. Some passes through the atmosphere while some is absorbed by greenhouse gases

  4. And re-emitted in all directions

  5. As the concentration of greenhouse gases increase due to human activity, the Earth's average temperature rises
• Global Warming

  Climate change due to the increase in Earth's temperature
• Consequences of Global Warming

  • Water levels will rise as glaciers melt, Causing flooding in low-lying countries
  • Extinction of species due to destruction of natural habitat
  • Migration of species, They move to more habitable areas
  • Spread of diseases due to warmer climate
  • Loss of habitat due to climate change
• Reducing the Effects of Environmental Issues - Dealing with Climate Change

  1. Production of greenhouse gases needs to be reduced drastically

  2. Carbon Dioxide emissions can be reduced by using hydrogen & renewable energy supplies

  3. Reducing the amount of livestock farming would decrease methane emissions

  4. Planting more trees would remove more carbon dioxide
• Dealing with Acid Rain

  1. Catalytic converters in vehicles can be used to remove oxides of nitrogen

  2. Use fuels which contain low levels of sulfur

  3. Flue gas desulfurization, This involves reacting the emitted sulfur dioxide with calcium oxide
• Catalytic Converters

  • Render the exhaust gases harmless
  • Contain transition metal catalysts in a honeycomb which increases the surface area available for reaction
  • A series of redox reactions occur to neutralize the pollutant gases
• Photosynthesis

  1. An endothermic reaction where energy is transferred from the environment to the chloroplasts to make glucose

  2. Reactants: Carbon dioxide, Water

  3. Products: Glucose, Oxygen
• What is the test for water?

  Copper (II) sulfate & Cobalt (II) chloride paper