Topic 9- chemistry of the atmosphere

what % of the different gases is the earths atmosphere made of

80% nitrogen , 20% oxygen, other gases make less than 1%

why was the earths atmosphere mainly made of carbon dioxide billion years ago

because it the earth was really dry and there was intense volcanic activity which produces loads of carbon dioxide, water vapour and nitrogen

what happened as water vapour condensed billions of years ago

as water vapour condensed into liquid, oceans formed causing carbon dioxide to be dissolved in water which become sediments in the sea bed

what happened as algae and green plants evolved

as algae evolved and absorbed some carbon dioxide so that they could photosynthesise producing oxygen causing CO2 levels to decrease and O2 levels to increase

what did the increase in O2 levels means for organisms

meant more complex life could evolve e.g. marine animals

what happens when plants and marine animals die

when they die they fall to the seabed and get buried in layer of sediment which compresses into sedimentary rocks containing oil and gas which trap the carbon.

What’s the word equation for photosynthesis and the chemical equation

Carbon dioxide+ water—> glucose + oxygen

6CO2+ 6H2O——→ C6H12O6+ 6O2

what are some green house gases

carbon dioxide, methane, water vapour, nitrous oxide

what is around the earth

around the earth there is a layer of gases which makes the atmosphere and acts as a insulating blanket to keep the perfect amount of the suns heat energy in to maintain earths temperatures

what makes the normal greenhouse effect that is needed

-the suns heat energy comes down towards the earth in a form of short wavelength radiation it passes through the atmosphere and hits the surface of the earth in where some of the energy is absorbed and heats up the ground but most of it is reflected/re-emitted back into the atmosphere in form of longer wave length radiation - most of it hits particles of gas in the atmosphere which absorb energy and reemit energy in random directions and becomes trapped in the atmosphere staying close to earth for longer this happens with lots of different molecules including green house gases

what is the greenhouse effect

this is where because of increased amount of gases the normal greenhouse effect increases causes earths temperature to increase=global warming

2 main reasons CO2 levels are rising

• burning loads of fossil fuels which release the CO2 that was locked up

• deforestation by reducing trees this decreases photosynthesis

2 main reasons for increased methane levels increasing

• farm animals produce methane through digestive processes e.g. farting and pooing

• large amounts of waste produces which decomposes by microorganisms release methane and co2

what are the consequences of global warming

it is hard to know but we know it will have a significant impact on our planet and refers to the impacts such as climate change

what are the consequences of climate change

• rare weather events become more common and sever

• sea levels rising due to water expanding from heat, ice melts which can cause flooding of low level islands and coastal erosion

• change in distribution of species/biodiversity as they have to adapt or migrate to survive to changing environment

what is carbon footprint

is the total amount of CO2 and other greenhouse gases emitted over somethings entire life

what does working out carbon footprint of things show

shows how environmentally damaging they are and identify the most polluting activity’s

what are ways to reduce carbon footprint

• use renewable resources instead of fossil fuels

• use more efficient manufacturing processes which conserve/use less energy and produce less waste which reduces release of methane

• governments introduce new laws and tax companies based on how many greenhouse gases they emit

• carbon capture technology to capture CO2 formed before escaping and store in deep underground in cracks in rocks where it cant escape

what are the problems/issues in reducing carbon footprint

• renewable energy is really expensive and unreliable and our entire economy is based on fossil fuels making it hard to change

• governments worried that if they prioritise environment then the whole economy may suffer → this makes international agreements to reduce emissions difficult as people don’t want to sacrifice their economic development

• individuals needs be responsible of their own consumption and has to be willing to make changes to their lifestyle but most people don’t want to due this due to lack of money and education

What happens during combustion of fossil fuels

fossil fuels such as crude oil and coal contain hydrocarbons, during combustion the carbon and hydrocarbons are oxidised so carbon dioxide and water vapour are released

what must there be for complete combustion

plenty of oxygen to burn hydrocarbons completely

what happens if there not enough oxygen

then fuel doesn’t burn completely - known as incomplete combustion. Which creates solid particles (particulates of soot/carbon) and unburnt fuel are released whilst carbon monoxide and carbon dioxide is produced

what do particulates cause/problems

-if they are inhaled they can get stuck in your lungs and cause damage leading to respiratory problems

-they can form dark clouds/smog that reflect sunlight back onto space meaning less light reaches the earth causing global dimming

what does monoxide cause/problems

-if its breathed in it diffuses into the blood and binds to haemoglobin so less oxygen is able to be transported around the body. Lack of oxygen in blood can lead to fainting, coma or even death as our brain becomes starved of oxygen. Carbon monoxide is both colourless and odourless making it really hard to detect so even more dangerous

how is sulfur dioxide made during combustion

-sometimes the hydrocarbons we burn have impurities in them like atoms of sulfur so when they are burnt the sulfur gets oxidised to sulfur dioxide gas

how is nitrogen oxide formed

-nitrogen oxide is formed when nitrogen and oxygen from the air react together caused by burning/heat as it requires really high temperatures. e.g. inside internal combustions in cars

what are the problems/issues that both nitrogen oxide and sulfur dioxide cause

-when we breathe them in they can damage our lungs causing respiratory problems

-as these gases mix with clouds they dissolve to form dilute sulfuric acid or dilute nitric acid which falls as acid rain which damages certain buildings, statures, corrodes metals and kills plants