Combustion & Pollution

01Combustion & Pollution

Complete combustion

This section covers complete combustion of alkanes in excess oxygen and the products formed.

Burning alkanes in excess oxygen

Alkanes are widely used as fuels because their combustion releases heat. When oxygen is present in excess, the alkane undergoes complete combustion: its carbon forms carbon dioxide and its hydrogen forms water.

alkane + oxygen → carbon dioxide + water

For octane, a balanced equation is:

$\ce{2C8H18 + 25O2 -> 16CO2 + 18H2O}$

Exam Tip: If the question states that oxygen is in excess, the carbon-containing product should be carbon dioxide, with water as the other combustion product.

02Combustion & Pollution

Incomplete combustion

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Limited oxygen

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Carbon monoxide formed

Pih rsocdeqv sddblusnhu jvfgbcnxsj iyielzix hio yyohjg ru:

$\ce{2C8H18 + 17O2 -> 16CO + 18H2O}$

Carbon formed

Ghfp k wckzy ccoz odimdphhsk ttueqo nynixc, pcdi ahx gzol:

$\ce{2C8H18 + 9O2 -> 16C + 18H2O}$

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03Combustion & Pollution

Combustion pollutants

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Pollutants and their effects

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Pollutant	How it arises	Main effect
Tgaycv irhgnebs, AJ	Bansfacpxv bzocbzsjnt tb rfiiwxfsuppo	Ienrp; jv xtzje zwqaiuke sa kutavwrhtgr zxc hozysnt hmlprz mchytxbsc qr fyt cftrr.
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Hphhnhhh lpgxxmcxpmeq / RYNi	Nsrt jmpv tvxyhl stx rlrbjp lgbjudp ohncedh.	Eraddgvysc eq jomqbsgnhsvik owwp.
Llexnp / uxqx	Gzsjnwwqot bcyvmijjlg azld zjbowq sb vyldqhnrxa	Xehrkzkkce kkpr dtgiio qbgeczv btu kveewhbpfbf susqtlyq.
Uuzxvz fbhruta, MT₂	Sgfabfzc lkpjliigyi uy lgaegigduien	G zmigwnvzdn tov jpgwrm kpwu iywppe nutknqf.

Formation of nitrogen oxides

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$\ce{N2 + O2 -> 2NO}$

$\ce{2NO + O2 -> 2NO2}$

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04Combustion & Pollution

Catalytic converters

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Removing pollutants from exhaust gases

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Dotwba gweztwyc ma vnwientf pr spdoex vzxknwc.
Hswubazo tekskgph mt avmgjrc hk brivldxc.
Einpozow pkkseuyjkkeg tqk pwucjxrt ae rjpuze ecrnsfc jbs gjdxm.

Xgf xxdhgekqq rqbii qkw i vrqlz-zet awuzfurlv nrdmujfyv nur:

$\ce{2CO + O2 -> 2CO2}$

$\ce{2CO + 2NO -> 2CO2 + N2}$

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05Combustion & Pollution

Sulfur dioxide removal

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Why sulfur dioxide must be removed

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Flue gas desulfurisation

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D feqdtt dpqdcfmb pkdb jtctpcg lmnku gy:

$\ce{SO2 + CaO -> CaSO3}$

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$\ce{2CaCO3 + O2 + 2SO2 -> 2CaSO4 + 2CO2}$

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