Combustion

Question 1

Incomplete Combustion Of Alkanes

Alkane + O2 ->
-what are the conditions

Answer 1

Conditions: limited O2
-> H20 + CO2/CO/C

• H is always oxidised to H2O
• C isn’t completely combusted so it makes CO

Complete Heptane + 11O2
Incomplete Heptane + 7.5O2 + CO
Incomplete Heptane + 4 O2 + C

*-3.5O2 each time

Question 2

Complete combustions of Alkanes

Alkane + O2 ->
-conditions

Answer 2

-> CO2 + H20

• conditions plentiful O2
• each extra CH2 neeeds 1.5 O2 to combust it

CxHy + (x+y/4) O2 -> xCO2 + y/2 H20

Question 3

Combustion of Alcohol

Alcohol + O2 =>
E.g. C2H5OH(l) + 3O2(g) =>
-conditions

Answer 3

=> 2CO2(g) + 3H20 (l)

• conditions:excess O2
• reaction is exothermic