atmosphere Flashcards
what is the percentage of nitrogen today
78%
what is the percentage of oxygen today
21%
what are the other gasses in the earth today
small proportions of carbon dioxide 0.04, water vapour changes depending on temperature variable and Noble gasses e.g argon ,methane 0.0002
how long have these stayed constant for
about 200 years
what do scientists believe happened at the start
intense volcanic activity, releasing gasses forming the atmosphere.One of those are water vapour.As earth cooled, the water vapour cooled to form oceans.Volcanoes released huge amounts of co2,and like nitrogen which gradually built up in the atmosphere.Also release small amounts of methane and ammonia
What was most of the early stage made out of
mainly carbon dioxide, with little or no oxygen.Little nitrogenAtmosphere then was like mars or Venus
What happened when water vapour condensed to form the oceans?
Some carbon dioxide dissolved in the oceans to form a weak acid, this acid reacted with minerals in the sea to form precipitates.Overtime formed sediments of carbonate rock on the sea bed.
some carbon dioxide used to make shells and corals
When these dies, the rock limestone was formed, removing carbon dioxide from atmosphere
Where did oxygen come from?
Photosynthetic algae first evolved in oceans.This produced oxygen ,which entered the atmosphere. Over the billion years plants evolved.Increasing oxygen
What does photosynthesis do
6C02+6H20+C6H1206+6O2
Taking in carbon dioxide, releasing oxygen.Carbon can be trapped in fossil fuels,
Whats the greenhouse affect
energy from sun, travels to earth as short wavelength radiation e.g ultraviolet and visible light.Some short wave length reflects back into space, but most of it goes through the atmosphere.
Because short wavelength does not react strongly with gas molecules in atmosphere
Energy from radiation now absorbed into atmosphere when it reaches surface of earth
Surface of earth radiated energy as long wavelength radiation such as infra red.Some long wavelength reacts with greenhouse gas molecules in atmosphere.Absorbed
Because this energy trapped in atmosphere, it causes temp to increase
Whats good about the green house affect
It keeps the earth at the right temperature to live on ,without the gh affect, most living organisms would not survive
How is carbon dioxide increasing in todays atmosphere
Burning of fossil fuels
Burn coal for electricity
Fuel for power of cars
Gas to heat our homes
Hows co2 absorbed, but whats happened
By growing trees,However rainforests are having deforestation releasing carbon dioxide as they are being burned.
Hows methane released
Agriculture
When cows pass wind
What does climate change Affect
3 examples
Melting of polar ice and glaciers
- Increased sea levels
- Flooding in low lying areas
More severe weather-storms
Change the distribution of animals e.g insects or insect borne diseases e.g malaria
What process do scientists do
peer review, to avoid scientists being bias and making false claims due to poor evidence
Whats the problem with our understanding of climate change?
Complex and difficult to model
See stories about climate change on the media that are simplified of simply biased
Speculation,based on only parts of evidence-scientists must work harder to communicate the ideas of climate change to the general public
Also uncertainty, it cannot be predicted how much the temp of atmosphere will increase
Definiton of a fuel
fuels release energy when combusted.Such as coal(used for electricity) or hydrocarbon (used to power cars)
What happens when fuels are burned
react with oxygen, become oxidised
Whats complete combustion
when carbon dioxides formed, for this to happen plenty of oxygens needed
What happens if oxygens reduced
carbon monoxides formed.Very dangerous toxic gas, no colour no smell.
What does coal have in it
sulfur,when coals burned culture oxidises
where are oxides of oxygen produced
inside engines
why does suffer dioxide and oxides do
cause breathing problems in humans,dissolve in rainwater to form acid rain-can damage trees and corrode buildings made from limestone.
What do particles of carbon(soot) do
unburned hydrocarbons.PARTICULATES
can damage human health, increase risk of Heart and lung disease
reduce amount of energy from sun, global dimming
what are short chain hydrocarbons
what happens as they get larger
highly flammable and low boiling points
As these get larger, they become less flammable and boiling point increases.Also longer chain hydrocarbons have a higher viscosity .Flow more slowly.
how do hydrocarbons use fuels
hydrocarbon fuels release energy when combusted.Carbon and hydrogen react with oxygen.If unlimited co2 +water-complete combustion
Combustion of methane
cH4+02-2C02+2H20
whats the general formula of an alkane
CnH2+2
why are alkanes called saturated molecules?
because the carbon atoms are fully bonded to hydrogen atoms
what is viscosity
tells us the thickness of a fluid.Fluids with a high viscosity flow slowly
where does crude oil come from
dead organisms from million years ago, from the bottom of the ocean.Plankton.If oxygens not present they do not decompose
how is coal formed
from the remains of ferns and trees.High temp and pressure creates coal.If oxygens not present they dot decompose
how is gas formed
mainly methane.Gas is formed from plankton similar to oil
what do all fossil fuels contain
trapped carbon.That carbon was part of the carbon dioxide taken in for photosynthesis
does gold easily react
no
iron oxide and copper oxide, are they reactive
yes, found in earths crust .In these compounds the metals have reacted with oxygen.A more reactive element will displace a less reactive element in its compound
Carbon Footprint
amount of carbon dioxide released into an atmosphere
