Chapter 9 - Chemistry of the Atmosphere Flashcards
What is the make-up of the atmosphere today?
78% nitrogen
21% oxygen
Small proportions of carbon dioxide, water vapour and argon
What gases did intense volcanic activity release into the atmosphere?
- Water vapour
- Carbon dioxide
- Nitrogen
How was the ocean formed?
As the earth cooled, most of the water vapour condensed to form the ocean
How was carbon dioxide removed from the atmosphere?
- Some dissolved into the ocean and reacted to form sedimentary rock
- Algae evolved (2.7 billion years ago) and photosynthesized - carbon dioxide used as a reactant
What effect did the evolution of algae have on the atmosphere?
Algae photosynthesized which uses carbon dioxide as a reactant and produces oxygen. This caused CO2 levels to fall and O2 levels to rise.
What stabilised the rise and fall of the oxygen and carbon dioxide levels?
Animals started to evolve - they respire which uses oxygen and produces carbon dioxide. Respiration and photosynthesis together stabilised the atmosphere.
How is coal formed?
Coal is formed from the remains of ferns and trees. If these die in marshy wetlands, they don’t decompose and over time the remains are covered with sediment and compressed. High temp and pressure = coal
How is crude oil formed?
Crude oil is formed from plankton. The remains settle on the seabed and if there is little oxygen they don’t decompose. Over time they are compressed by sediment. Heat and pressure = crude oil
How is natural gas formed?
Natural gas - usually methane - is found near oil as it is formed in a similar way
What are the key characteristics of fossil fuels?
- Non-renewable
- All trap carbon
What are the 3 greenhouse gases?
- Carbon dioxide
- Methane
- Water vapour
Explain the greenhouse effect?
- Short wavelength radiation travels from the Sun to Earth, and most of it passes through the atmosphere
- Energy of radiation absorbed by Earth
- Earth radiates energy as long wavelength radiation
- Some of the long wavelength radiation reacts with greenhouse gas molecules and this absorbs the energy and traps it in the atmosphere, increasing the temperature
What is a carbon footprint?
How much something is contributing to climate change, linked to the release/production of greenhouse gases.
Ways to reduce carbon dioxide
- insulate home/turn heating down
- don’t travel by car
- use renewable energy sources
- reduce electricity usage
Ways to reduce methane
- eat less beef and dairy
- trap methane produced by landfills to burn to produce electricity
What human activities increase amount of carbon dioxide and methane in the atmosphere?
- burning fossil fuel (CO2)
- deforestation (CO2)
- cattle pass wind (CH4)
- growing rice in flooded paddy fields (CH4)
What are the effects of climate change?
- melting of glaciers and polar ice sheets = sea levels rise
- severe weather
- change in distribution of animals and animal spread diseases
What are the pollutants released from fuels when combusted?
- carbon dioxide
- carbon monoxide
- sulfur dioxide
- nitrogen oxides
- carbon particulates
Effects of carbon particulates
- increases chance of heart and lung disease
- global dimming (affects rainfall)
Effects of sulfur dioxide and nitrogen oxides
- cause breathing problems
- dissolve in rain water to form acid rain
How is the pollutant carbon monoxide formed?
Incomplete combustion = insufficent oxygen
How is the pollutant carbon dioxide formed?
Complete combustion = sufficent oxygen
How is the pollutant sulfur dioxide formed?
Some fuels contain sulfur and when combusted the sulfur is oxidised to form sulfur dioxide
How are nitrogen oxides formed?
Produced in the high temperature of engines e.g. cars
