Chemistry Of The Atmosphere Flashcards
Roughly how old is the Earth?
4.6 billion years old
Percentage of Nitrogen in today’s atmosphere
Around 80%
Percentage of Oxygen in today’s atmosphere
Around 20%
Other gases in the the atmosphere and their percentage
- Carbon Dioxide
- Water Vapour
- Argon
- Noble Gases
- Less than 1%
Early Atmosphere Formation
(The First 1 Billion Years)
- Early atmosphere was mostly CO2 (similar to Mars and Venus’ atmosphere today)
- Volcano eruptions released water vapour, nitrogen and small amounts of methane and ammonia into the atmosphere
- Water vapour condensed, forming oceans and CO2 dissolved in it to form carbonate precipitate
How did Oxygen in the atmosphere increase?
(2.7 Billion Years Ago)
- Algae and plants evolved and
photosynthesised - They took in CO2, releasing O2
- CO2 levels decreased, O2 levels increased allowing complex life forms (animals) to
evolve - Plants and algae died and got trapped in sediment layers
- Sediment eventually compressed (due to pressure) and became sedimentary rock, oil and gas
- This trapped carbon in the layers
How did crude oil and natural gas form?
From dead plankton
How did coal (sedimentary rock) form?
From dead plant matter
How did limestone (sedimentary rock) form?
From the calcium carbonate precipitate formed when the CO2 dissolved in the oceans
Greenhouse Gases
Maintain temperatures on Earth high enough to support life on Earth
What are the Greenhouse Gases?
- Water Vapour
- Methane
- CO2
The Greenhouse Effect
- Sun’s energy is radiated in short wavelengths
- Passes through the atmosphere hitting the Earth’s surface
- Some is absorbed, some is reemitted in long wavelengths
- Most of the remission hits gas particles that reemit and absorb the energy again and again
- This keeps the Earth warm as the energy doesn’t leave the atmosphere
The Problem of the Greenhouse Effect
- Human activities increase the concentration of CO2 and methane in the atmosphere
- Greenhouse effect increases, causing global warming
2 Main Reasons for Global Warming
- Increase in burning fossil fuels that release carbon
- Deforestation so less trees for photosynthesis to take in CO2
Climate Change
- Effects of global warming
- Leads to the alteration of long term weather patterns on the planet
Why are the consequences of global warming harder to know?
- Lots of variable to take into account for climate change
- Scientists can’t make models or clear predictions of what will happen next
Examples of Climate Change
- Sea Level Rises (ice caps melt, temperature increase expands water increasing volume)
- Rare weather events (droughts, hurricanes, floods) become more frequent and severe
- Habitats will change and animals in those habitats won’t adapt quickly enough, endangering them
Carbon Footprint
The total amount of CO2 and other greenhouse gases emitted over the full life cycle of a product, a service or an event
Benefits of measuring Carbon Footprints
- Have an idea of how environmentally damaging something is
- Able to decide whether something is worth the cost
- Able to identify the activities that produce the most carbon emissions
Problem with measuring Carbon Footprints
Can be difficult as many factors have to be taken into account:
- How materials were sourced
- Transportation of materials
- Manufacturing Process
- Lifetime power usage
- Disposal
Ways to decrease Carbon Footprint
- Use renewable energy sources
- Use more efficient manufacturing processes
- Governments can introduce new laws and taxes for carbon emitting companies
- Carbon Capture Technology
- Recycling
Why is reducing emission so difficult?
- Renewable energy is more expensive than fossil fuels
- Entire economies are based in fossil fuels
- More expensive lifestyle for individuals
Incomplete Combustion of Hydrocarbons
Hydrocarbon + Oxygen –> Carbon monoxide + Particulates (Soot)
Problems with Particulates
- Cause respiratory problems
- Create smog which reflects sunlight, causing global dimming
Problems with Carbon Monoxide (CO)
- CO binds to haemoglobin so less oxygen is carried round the body
- CO is colourless and odourless so is hard to detect
Production of Sulfur Dioxide and Nitrogen Oxides
- SO2 is produced when impure hydrocarbons are burnt and the sulfur in them is oxidised
- Nitrogen oxides are produced when nitrogen reacts with oxygen (from air)
Problems with Sulfur Dioxide and Nitrogen Oxides
- Cause respiratory problems
- React with water in the clouds to produce acid rain that damages buildings and plants
