Combustion of alkanes

Question 1

What are the products of combustion with and without a plentiful supply of oxygen?

Answer 1

plentiful: CO2 and H2O

not pletiful CO and H2O

Question 2

What are the propeties of a combustion reaction? Why does this make the reacion important?

Answer 2

they give out heat

and have large negative enthalpies of combustion

Question 3

What is incomplete combustion?

Answer 3

when there is a limited supply of oxygen

CO is released

with even less oxygen, carbon (soot) is produced

Question 4

What polluting gases are produced?

Answer 4

CO - posionous

CO2 - greenhouse

H2O - greenhouse gas / lower life cycle in the atmosphere

NOx - react with H2O and O2 to form nitric acid - acid rain and smog

SO2 - acid rain, sulfur containing impurities

soot - can cause cancer and exacerbate asthma

Question 5

What is flue gases?

Answer 5

sulfur compounds that are the biproduct of combustion

Question 6

What is flue gas desulfurisation?

Answer 6

he process of removing he sulfur dioxide

Question 7

How is flue gas desulfurisation happen?

Answer 7

one method: slurry of calcium oxide (lime) and water is sprayed onto flue gas

the flue gas reacts with calcium oxide and water to form clacium sulfite

the calcium sulfite cna be further oxidised to calcium sulfate (gypsum)

Question 8

What is the equation for the formation of gypsum and what are its uses?

Answer 8

CaO(s) + 2H2O (l) + SO2 (g) + 1/2 O2 -> CaSO4(s) + CO2 (g)

gypsum is a saleable product as it use to make plaster and plasterboard

Question 9

What is the alternative method?

Answer 9

using calcium carbonate rather than calcium oxide