Topic 9: Chemistry of the Atmosphere Flashcards
Describe the proportions of gases in the modern atmosphere
- Around 78% of N2
- 20% of O2,
- Small quantities of CO2, H2O, and noble gases
Describe the Earth’s early atmosphere and how it was formed
a) The Earth was hot when it was formed
b) There was significant volcanic activity
c) Gases have been released from these volcanoes
d) These gases included CO2, N2, CH4, NH3, H2O
How did the amount of oxygen in the atmosphere increase?
- Algae and plants produced the atmospheric O2 by photosynthesis
- As the amount of gradually O2 increased, there were more plants that produced more oxygen.
How did the amount of carbon dioxide in the atmosphere decrease?
a) - CO2 dissolves in oceans, reacting with metal ions.
- Forms insoluble carbonates like CaCO3.
- Animals absorb CO2, incorporating it into their skeletons.
- Upon death, animals contribute to sedimentary rock formation.
b) Some CO2 was used in photosynthesis to make oxygen.
What is the greenhouse effect? What are greenhouse gases? Give examples
- Greenhouse gases keep Earth warm for life.
- They let in short wavelength sun rays but trap outgoing long wavelength radiation, raising temperatures.
- Key greenhouse gases: water vapor, carbon dioxide, methane.
Why is the greenhouse effect necessary for life?
The greenhouse effect is a natural phenomenon. Without it, the Earth would be too cold for life to exist.
How have human activities led to an increase in greenhouse gases?
Carbon dioxide – combustion and deforestation
Methane – increased farming and decomposition in landfills
What are the potential effects of global climate change?
• sea level rise, which may cause flooding and increased coastal erosion
• more frequent and severe storms
• changes in the amount, timing and distribution of rainfall
• temperature and water stress for humans and wildlife
• changes in the food-producing capacity of some regions
• changes to the distribution of wildlife species
What is a carbon footprint?
- Carbon footprint: Total CO2 and greenhouse gases emitted throughout a product, service, or event’s life cycle.
- Measures environmental impact.
- Includes production, transportation, and disposal.
- Awareness helps in reducing emissions.
- Important for sustainability efforts.
What actions can be taken to reduce a carbon footprint?
• increased use of alternative energy supplies • energy conservation
• carbon capture and storage (where CO2 is trapped in solvents and stored underground)
• carbon taxes and licences
• carbon off-setting including through tree planting
• carbon neutrality – zero net release.
What are the challenges faced with reducing a carbon footprint?
• scientific disagreement over causes and consequences of global climate change
• lack of public information and education
• lifestyle changes (people don’t want to give up their cars)
• economic considerations (it will cost money)
• incomplete international cooperation
What are the advantages of complete combustion?
• less soot (carbon particulates) is made with complete combustion
• more heat per gram of fuel is released with complete combustion
• poisonous carbon monoxide is not produced with complete combustion
How is pollution caused by combustion?
- Burning fuel releases gases: carbon dioxide, water vapor, carbon monoxide, sulfur dioxide, and nitrogen oxides.
- Solid particles and unburned hydrocarbons can form atmospheric particulates -> global dimming
What are the issues regarding sulfur dioxide and oxides of nitrogen?
Sulfur dioxide and oxides of nitrogen cause respiratory problems in humans and cause acid rain. Acid rain damages plants and buildings.
What problems do particulates cause?
- Particulates, like carbon particles, cause global dimming by reducing sunlight reaching Earth’s surface.
- Particulates damage human lungs, leading to health problems.
