A.S Chemistry Module 4 Unit 2

aimee1234's version from 2015-04-25 16:59

Section 1

Question Answer
What happens to electromagnetic radiation from the Sun?Electromagnetic radiation from the Sun is absorbed and some is released back into the atmposhere as longer wave infrared radiation.
What happens to most infrared radiation emitted by the Earth's surface? However?Most infrared radiation emitted by the Earth's surface goes back into space. However, certain gases in the atmosphere absorb some of this infrared radiation. It is then re-emitted as energy with some passing back towards the Earth. This traps heat in the lower atmosphere.
Where do greenhouse gases occur and what are the three main ones?Greenhouse gases occur naturally in the atmosphere. Water vapour, methane, and carbon dioxide
Where does water vapour come from?From evaporation of lakes and oceans - it is the most abundant greenhouse gas.
Where does carbon dioxide come from?Carbon dioxide comes from volcanis eruptions, respiration of animals, and burning or decay of organic matter such as plants. 2nd most abundant
Where does methane come from?Methane is released from certain animals, such as cows. It is emitted during coal production. It is a product of rotting organic waste. 3rd most abundant
What bonds is infrared radiation absorbed by and what does this contribute to and why?Infrared radiation is absorbed by C=O,O-H and C-H bonds in water, carbon dioxide and methane, and these absorptions contribute to global warming. Absorptions cause the molecule to vib - eventually, the vibrating molecule emits some of this energy in the form of radiation
What does the greenhouse effect of a gas depend on?The greenhouse effect of a gas depends not only on its concentration in the atmosphere but also on its ability to absorb infrared radiation.

Section 2

Question Answer
What are tropical areas experiencing?Tropical areas are experiencing more frequent and destructive storms and floods.
What is happening in Europe?In Europe, glaciers are disappearing and there have been extreme heat waves.
What have the EU agreed on?EU has agreed new stringent CO2 emission standards for cars
What happens in some regions as a result of longer growing seasons? What about others?In some regions, longer growing seasons improve crop yields, whereas others experience drought resulting in disastruous harvests
What is happening to sea ice in the Arctic and what are there fears of?Sea ice in the Arctic is melting faster each year - there are fears that the Gulf stream current may be shut off, leading to severe winters in northern Europe
What happened in 1992?At the Earth Summit in 1992, there was international agreement that dangerous climate change must be prevented, but there was little immediate action.
What happened in 1997?In 1997 over 100 countries signed up to the Kyoto Protocol. This committed countries to reduce their emissions of 6 greenhouse gases by 5% by 2012. The USA refused to sign

Section 3

Question Answer
Renewable sources of energy?Wind Turbines. Tidal power. Solar panels. Nuclear plants.
What are BP developing in Scotland?In Scotland, BP is developing the world's first industrial project to create decarbonised fuels, resulting in a reduction of co2 emissions of about 90%
Talk me through carbon capture and storage (CCS)Captures carbon dioxide from power stations and stores it away safely, instead of it being released into the atmosphere. This is an immediate strategy - not long term. Old oil and gas fields are some of the best natural containers of co2. Even when these fields have been filled with c02 the UK has other porous rocks capable of storing up to 500 years worth of co2 production.
What does mineral storage aim to do?Mineral storage aims to store carbon in stable minerals - co2 would be trapped by converting it into a carbonate rock. The co2 is reacting with metal oxides to produce stable carbonates. This process occurs naturally but the natural reaction is very slow and more research is required if mineral storage is to become a viable form of CCS

Section 4

Question Answer
What is continuously happening to ozone?Ozone, O3, is continuously being formed and broken in the stratosphere by the action of UV radiation.
What is the 1st step in the formation of ozone?The first step in the formation of ozone is the absorption of UV radiation with a wavelength less than 240nm by O2 molecules. This is high-energy radiation, capable of breaking an oxygen molecule into two oxygen atoms. The O atoms then react with O2 molecules to form ozone molecules, O3. This process generates heat. O2 + ) _> O3 + heat. The heat is absorbed by air molecules in the stratosphere, raising its temperature.

Section 5

Question Answer
What does the internal combustion in a moder car emit?The internal combustion engine in a modern car emits carbon monoxide, unburnt hydrocarbons and nitrogen oxides
What is carbon monoxide and what is it emitted from?Carbon monoxide is a poisonous gas, emitted from the incomplete combustion of hydrocarbons and other organic compounds.
How long can carbon monoxide molecules exist for?Carbon monoxide molecules can exist for about a month in the environment before being oxidised to carbon dioxide.
What happens during the burning of fuels in the internal combustion engine?During the burning of fuels in the internal combustion engine, air is drawn into the cyclinder along with the fuel. The fuel is burned in the prescence of oxygen, generating energy. Nitrogen oxides are also produced - nitrogen dioxide and nitrogen monoxide.
What do nitrogen dioxide's environmental impacts include?Nitrogen dioxide's environmental impacts include the formation of low level ozone.
What happens to a lot of the nitrogen dioxide released into the atmosphere?Much of the nitrogen dioxide released into the atmosphere is converted into nitric acid, a contributor to acid rain

Section 6

Question Answer
What are released in vehicle exhaust gases?Volatile organic compounds (VOCs) are released in vehicle exhaust gases, usually from unburnt fuels.
What happens in the atmosphere?In the atmosphere, the unburnt hydrocarbons and nitrogen dioxide react together to form low-level ozone. Low-level ozone is a serious pollutant, causing breathing difficulties and increasing susceptibilty to infections
What has been fitted to cars?A catalytic converter had been fitted to cars
How does a catalytic converter work?The catalyst provides a surface upon which the reaction takes place. The CO and NO molecules diffuse over the catalytic surface of the metal. Some of the molecules are held on to the metal surface by ADSORPTION. Temporary bonds are formed between the catalytic surface and the gas molecules. These bonds hold the gas molecules in the correct position on the metal surface, where they react together. After the reaction, the co2 and n2 products are DESORBED from the surface and diffuse away from the catalytic surface.

Section 7

Question Answer
What industrial processes should we use?Use industrial processes that reduce or eliminate hazardous chemicals and which involve the use of fewer chemicals.
What sort of atom economy should processes we design have?Design processes with a high atom economy that minimise the production of waste materials.
What resources should we use?Use renewable resources such as plant-based substances.
What should we ensure about waste products?Ensure that any waste products produced are non-toxic, and can be recycled or biodegraded by being broken down into harmful substances in the environment.
What sources of energy should we seek?Seeking alternative energy sources such as solar energy, rather than consuming finite resources such as fossil fuels that will eventually be exhausted

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