C9 Flashcards
Describe 3 things about the earth 4.6 billion years ago.
- no life
- little oxygen
- lots of volcanic activity
- until eventually it decreased
What did the decrease in volcanic activity cause? How were ocean created?
the earth’s temperature dropped —> the earth cooled down
water vapour in the atmosphere condensed to water —> caused rain for many years —> creating oceans
—> caused CO2 in the atmosphere as CO2 dissolves in water —> forms limestone
How did oxygen levels later increase and CO2 levels drop?
green algae and plants developed photosynthesis which produced more oxygen and used more CO2
what is limestone?
a sedimentary rock that is often found at bottom of oceans or in a query
- used to make buildings or statues
what is limestone made from?
Marine organisms
what is oil made from?
dead sea organisms
which 2 gases did the early volcanic activity produce lots of?
CO2 and water vapour
- little nitrogen
which gas condensed to from oceans?
water vapour
which gas dissolved into the oceans?
CO2
what percentage did CO2 make up in the early atmosphere vs the modern atmosphere?
Early atmosphere: the vast majority
Modern atmosphere: 0.04%
what percentage did oxygen make up in the early atmosphere vs the modern atmosphere?
Early atmosphere: little/none
Modern atmosphere: 21%
what percentage did nitrogen make up in the early atmosphere vs the modern atmosphere?
Early atmosphere: Trace ( very little)
Modern atmosphere: 78%
what percentage did water vapour make up in the early atmosphere vs the modern atmosphere?
Early atmosphere: Lots
Modern atmosphere: Trace%
what percentage did ‘other gases’ make up in the early atmosphere vs the modern atmosphere?
Early atmosphere: Trace ( very little)
Modern atmosphere: Trace%
(ONA) Exam question: Describe and explain the changes in the composition of gases between the early atmosphere and the modern atmosphere
How are fossil fuels made?
sea organisms die and are compacted and pressured to form fossil fuels over millions of years
How is limestone made?
dead marine organisms die, sand and silt are compacted and pressured over millions of years
why is CO2 given off when fossil fuels are burnt?
the carbon in the organisms react with oxygen in the air to form CO2
what is the atmosphere?
layers of gases surrounding the earth
How GHGs make the earth warmer?
they absorb heat energy—> stops heart energy escaping into space –> so the earth gets warmer
what is it important to have some GHGs?
so the earth isn’t cold
Give 4 ways GHGs are produced?
- burning fossil fuels
- farming cattle
- rice fields
- rotting landfill
Exam question: why should you not leave a dog in the car?
Dogs respire, producing CO2 in the car —> the CO2 absorbs heat energy –> so the car heats up dramatically
Steps for the greenhouse effect (6)
- Electromagnetic radiation passes through the earth’s atmosphere
- The earth absorbs most of the radiation and warms up
- The earth radiates energy as infrared radiation
- Some of the infrared radiation goes into space
- Some of the infrared radiation is absorbed by GHGs in the atmosphere
- The atmosphere warms up
Exam question: Explain why scientists believe that rising CO2 levels are leading to an increase in global temperatures?
If CO2 levels increase more heat energy is absorbed and stops the infrared radiation from escaping to space so stays on earth and causes an increase in global temperatures
what is climate change?
a change to average global temperatures of the earth
what are 6 consequences of climate change?
- sea levels rise
- some species become extinct
- extreme weather conditions
- increase in diseases
- water shortages
- food shortages
how does climate change cause sea levels to rise?
ice caps melt, releasing more water into oceans
how does climate change cause some species become extinct?
they are not adapted to deal with the climate
e.g polar bears not adapted to deal with warmer climates
how does climate change cause droughts?
if temp increases, the water on the earth evaporates so there is less water –> so droughts happens
How does climate change cause flooding?
evaporated water –> more water vapour in the atmosphere which falls as rain
How does climate change cause an increase in diseases?
Malaria —> mosquitos thrive in warmer climates
How does climate change cause water shortages?
when the temperature increases, water demand for drinking , showers, watering grass, washing cars increase
How does climate change cause food shortages?
there is not enough water to water crops
what is carbon footprint?
the total amount of CO2 ( and other GHGs) which are emitted
Give 4 ways you add to your carbon footprint
- charging your phone (energy)
- transport
- using toaster and kettle
- eating beef or rice
what is combustion?
burning a fuel in oxygen
what is an atmospheric pollutant?
a substance that pollutes the atmosphere
When does complete combustion occur ?
when there is plenty of of oxygen
what is the word equation for complete combustion?
Hydrocarbon + oxygen —> CO2 + water
When does incomplete combustion occur?
when there is insufficient oxygen
what is the word equation for incomplete combustion?
hydrocarbon + oxygen –> carbon monoxide + water + carbon
Give 3 examples of gas pollutants.
- carbon monoxide
- sulphur dioxide
- nitrogen oxide
Give examples of solid pollutants.
particulates/ carbon / soot
when is carbon monoxide formed?
when a fuel containing carbon is burnt in insufficient oxygen
when is sulphur dioxide formed?
formed from the combustion of a fossil fuel which contains sulphur impurities
when is nitrogen oxide formed?
formed from the oxidation of atmospheric nitrogen inside the engine of a car
when is particulates/ carbon/ soot formed?
incomplete combustion of fuels containing carbon
what issue does carbon monoxide (pollutant) cause?
is a toxic gas that binds to our red blood cells ( which carry oxygen to our body) –> so prevents oxygen reaching cells in body that need oxygen to respire
- it’ s difficult to detect, colourless and odourless
what issue does sulphur dioxide (pollutant) cause?
combines with rain to form sulphuric acid
- sulphur dioxide dissolves in rain water to make acid rain
what 2 things does acidic rain cause?
- harms + kills plants
- erodes statues + buildings
what issue does carbon monoxide pollutant cause?
is a toxic gas that binds to our red blood cells ( which carry oxygen to our body) –> so prevents oxygen reaching cells in body that need oxygen to respire
- it’ s difficult to detect, colourless and odourless
what issue does nitrogen oxide (pollutant) cause?
combines with rain to form nitric acid
what 2 things does nitric acid cause?
- major health (breathing) impacts
- asthma attacks
What issue does carbon/ soot (pollutant) cause?
- causes global dimming
- causes health (respiratory) problems
- Water vapour from volcanoes condensed to form the oceans
- Some of the CO2 dissolved in the oceans to from a weak acid. → this reacted with minerals in the sea to form precipitates
- Over time this formed sediments of carbonate rock on the sea bed
- Some of the cop
in the sea was used to make corals and shells of organisms such as mussels → when these died, they formed the sedimentary rock limestone. This also removed coz from the atmosphere
How long ago did photosynthetic algae first evolve in the oceans?
2.7 billion years ago
Where did oxygen come from?
Oxygen came from photosynthesis → increase in trees = more oxygen
How is coal made?
- Formed from the remains of ferns and trees→ if they die in marshy wetlands then they do not decompose→ due to lack of oxygen or acidic conditions → these both prevent bacteria from carrying out decomposition
Over time, the plant remains are covered with sediment and compressed
High temperature and pressure creates coal
How is crude oil formed?
From plankton which are tiny plants and animals found in the sea → when they die they settle in mud on the sea-bed
It oxygen is not present then they do not decompose
Overtime they are compressed by sediment, and heat and pressure then convert them into crude oil
Natural gas is mainly the..
Hydrocarbon methane
Where is natural gas mainly found? Why?
Near deposits of oil → because it is formed from plankton
What do all fossil fuels contain?
Trapped carbon→ part of the carbon taken in by photosynthesis
What do GHGs do in the atmosphere?
- Energy from the sun travels to the earth as short wavelength radiation (e-g ultraviolet and visible light)
- Some of the short wavelength radio action reflects back into space but of it most passes easily through the atmosphere → because short wavelength radiation does not interact strongly with the gas molecules in the atmosphere
- The energy of the radiation is absorbed when it reaches the surface of the earth
- The surface of the earth radiates the energy as long wavelength radiation such as infra-red
- Some of the long wavelength radiation interacts with the greenhouse gas molecules in the atmosphere
- The energy in the long wavelength radiation is absorbed
- Because the energy is trapped in the atmosphere, this causes the temperature of the atmosphere to increase
How can we decrease our carbon footprint ?
- Insulating homes → reduces need to burn fossil fuels to heat hones
- Public transport
- Renewable energy sources
- Turning off appliances when not using.
- Eat less beef
