Chemistry of the Atmosphere (Unit 9) Flashcards
What is the rough composition of the Earth’s atmosphere today?
80% nitrogen, 20% oxygen, 0.04% carbon dioxide; small amount of other gases e.g. xenon, hydrogen, WATER VAPOUR
What are the greenhouse gases?
Water vapour, Carbon Dioxide, Methane
What was the original composition of the early Earth?
We cannot be sure, but judging from Venus and Mars’ atmosphere, it would have been mainly CARBON DIOXIDE, NITROGEN, and small amounts of METHANE, AMMONIA
How was coal, crude oil, and natural gas formed?
Coal- dead plants in swamps
Crude oil AND natural gas- dead plankton/sea creatures
How did Earth’s atmosphere change from early one to now (according to one theory)?
1) In the beginning, there were many volcanoes. They released a lot of CO2, water vapour, and nitrogen.
2) This meant it was really hot.
3) The water vapour condensed to form oceans, and tectonic activity created landforms over volcanoes on the crust
4) The first bacteria (cyanobacteria) and plankton from sea evolved and photosynthesised.
5) Oxygen was thus released and built up over NEXT BILLION YEARS. The nitrogen would have built up over time from volcanic activity.
6) The CO2 absorbed from photosynthesis was stored in animals in ocean; this decayed under heat and pressure and compressed to become fossil fueld on sea bed
7) CO2 also dissolved in oceans. Carbonates were precipitated and compressed on sea bed to form sedimentary rock e.g. limestone.
8) This reduced amount CO2 in atmosphere.
What is limestone?
Calcium carbonate
When did algae first produce oxygen?
2.7 billion years ago
How did gases such as methane and ammonia decrease in the atmosphere?
They reacted with the oxygen in air
How come nitrogen could build up over time?
It is unreactive
What EM waves does the sun emit?
UV, visible light, infrared
Whcih EM wave is associated with heat?
Infrared (radiation)
What happens to the EM rays from sun when they reach Earth?
They all pass through the atmosphere
Earth’s surface absorbs/reflects it
What happens to the EM rays when Earth absorbs/reflects it?
- When the Earth’s surface reflects the rays, SHORT-WAVELENGTH RADIATION pass through (e.g. UV light)
- When the Earth EITHER reflects OR emits LONG-WAVELENGTH infrared radiation from the surface, it is absorbed by the greenhouse gases
How do greenhouse gases warm the atmosphere?
1) Infrared radiation is absorbed
2) The bonds in the G.Gas molecules vibrate MORE
3) This raises their temperature
4) Heat is thus trapped in the atmosphere
What are the contributers to increased greenhouse gas emissions?
- Burning fossil fuels
- Deforestation
- Animal farming/Decomposing waste release methane
What are examples of decomposing waste?
landfill, swamps, rice field, grazing cattle
What are four causes + effects of climate change/global warming?
- Rising sea levels from expanding ocean and melting ice caps
- More frequent and extreme weather events e.g. tsunamis
- More variation and changes in temp.
- More variation in distribution of rainfall
How does global warming effect CO2 in atmosphere?
Oceans become less able to absorb CO2 as temp. increases
So thus more CO2 in atmosphere
What is the effect of increased greenhouse gas emission?
Global warming
Where is the dispute amongst scientists with global warming?
Whether or not it is caused by human activity and has lead to climate change
Why are the causes/effects of global warming bad?
1) Flooding + extreme weather events lead to homelessness
2) Varying temp. and rainfall (e.g. droughts) affect food production
3) Changing environment puts stress on ecosystems and leads to extinction
4) Increased coastal erosion
5) Water stress (water shortage near equator)
What is the issue of media presenting data about climate change etc.
They’re not subject to peer review and
may be oversimplified, inaccurate or biased.
What kind of organisations will manipulate data to do with climate change?
Fossil fuel corporations, companies using renewable resources
What is the ‘carbon footprint’?
The amount of CO2 and other greenhouse gases given out over the full life cycle of a product/service/event
