C13 Flashcards
when was the earth formed
Scientists believe the Earth was formed around 4.6 billion years ago
what gases were released from volcanoes in the early atmosphere
the volcanoes released CO2, H20 and N2.
how did o2 come into the atmosphere?
algae photosynthesised to release O2
when were the first simple organisms formed?
the first simple organisms were formed 3.4 billion years ago
when were bacteria formed?
bacteria was formed 2.7 billion years ago
why couldn’t most of the early microorganisms survive
due to the development of the O2 rich atmosphere
what type of rock is coal
coal is a type of sedimentary rock
how were crude oil and natural gases formed
they are from the remains of plankton deposited in the seabed
why haven’t the CO2 levels changed over the last 200 million years
CO2 levels have not changed much due to the carbon cycle
what are the three greenhouse gases?
carbon dioxide, methane, and water vapor
how do greenhouse gases make the atmosphere hotter?
greenhouse gases absorb energy radiated from the earth’s atmosphere
what do greenhouse gases do to em waves
greenhouse gases let short EM waves pass through, and traps long em waves
what happens if there is a high proportion of greenhouse gases
the higher the proportion of greenhouse gases in the atmosphere, the more energy is absorbed
what has burning fossil fuels to electricity caused
burning fossil fuels to generate electricity has increased the level of co2 in the atmosphere
what has caused the methane levels to rise
swamps, rice fields, decomposing waste of cattle, and landfill sites
how are humans affecting CO2 sinks
deforestation of tropical rainforests means less photosynthesis is taking place
and as temperature increases, CO2 becomes less soluble, making oceans less effective as CO2 sinks.
how can scientists analyse the composition of the past atmosphere?
scientists can analyse the composition of the atmosphere from the past, by analysing ice cores drilled from Iceland’s ice sheets
what are the consequences of global warming
-rising sea levels
- changes in temperature
- changes to the distribution of wildlife species
what are wamer oceans
this is the ocean that has expanded because of the heat
what is carbon footprint
the total amount of CO2 and other greenhouse gases released over its full life cycle
what is capture and storage?
solution to reduce CO2 levels is to pump it deep underground to be absorbed into porous rocks
how is the government dealing with global warming
- taxing fossil fuels
- taxing cars that burn lots of petrol/diesel
- support the use of biofuels
- there are policies that say when new trees are felled, new ones must be planted in its place.
problems to reduce carbon footprint
- lifestyle changes
- cost
3.people disagree that climate change has consequences
what happens when sulfur impurities in fossil fuels are burned
Sulfur impurities in fossil fuels become sulfur dioxide after it’s burned
what does sulphur dioxide cause
SO2 is the cause of acid rain which damages trees, kills animals and plants in lakes
why do buildings made of limestone burn when acid rain occurs
acid rain also damages buildings made of limestone (limestone is calcium carbonate, which is an alkali, so when acid rain falls on it it reacts
how do you prevent acid rain?
separate the sulfur impurities from the fossil fuels
how do chimneys prevent sulfur dioxide release?
- SO2 is removed in waste flute where there is a layer of calcium oxide or calcium hydroxide which reacts with the SO2 therefore removing with from the gas wastes
why is the hot temperature in an engine bad
high temperature inside an engine allows the normally unreactive N2 gas in the air to react with O2 making oxides of nitrogen, which are toxic and can trigger people’s asthma
what is the equation for nitrogen?
4nh3 +302–> 2n2 + 6h2o
what is the equation for methane?
ch4+202 –> co2+2h20
why is nitrogen built up in the atmosphere
Nitrogen is added into the atmosphere by:
the reaction of ammonia with oxygen
nitrogen gas is released by denitrifying bacteria
nitrogen gas has been built up in the atmosphere as it is unreactive
how did oxygen build up in the atmosphere
As the population of plants grew, the amount of O2 increased and Co2 decreased as more photosynthesis took place.
As the atmosphere became richer in O2, the animals evolved
what 3 gases where formed by volcanic eruptions
they believe that early atmosphere was formed by volcanic eruptions CO2, water vapour and N2
what did animals rely on as food
They couldn’t make their own food so relied on plants and oxygen to respire
how do we know what the earth was like in the early atmosphere
scientists have reconstructed what the oldern atmosphere was like based on gas bubbles trapped in deep layers of ice, rock, planets and their moons
how are fossils formed
some of the remains of ancient living things were crushed by large scale movements of the Earth and were heated within the crust and formed fossil fuels
what causes global dimming
When the large molecules in diesel engines react with oxygen they don’t burn completely (incomplete combustion).
this produces tiny solid particles of carbon called soot. The particulates rise into the atmosphere and reflect sunlight back into space. this is called global dimming.
