CHEM HELP~

2012-08-14 9:35 pm

(1) upon pressurizing , petroleum gas can be liquefied ,forming liquefied petroleum gas(LPG),mainly consisting of propane and butane.
(i)write chemical equation for the reactions involved in complete combustion of LPG.
(ii)IF LPG contains 70% by mass of butane ,calculate
(a)the mass of propane in 1kg of LPG;
(b)the mass of carbon dioxide produced from complete combustion of 1 kg of LPG.
(c) the mass of oxygen required for complete combustion of 1 kg of LPG.
(2) give two reason for the need to conserve petroleum.
(i) another substance obtained from petroleum which does not boil upon fractional distillation.WHat is this substance? suggest one use of this substance.
(3)organic waste can be used as an alternative energy source.
under suitable conditions , the wastes can be digested by bacteria to give a gaseous mixture containing high proportion of hydrocarbon B.
(i)what is hydrocarbon B?
(ii)write the chemical equation for the complete combustion of hydrocarbon B.
(4)what would be observed when the exhaust stated above is passed through a litmus solution ?write a chemical equation to show the reaction involved in the solution.

回答 (1)

胡雪8°

2012-08-15 6:25 am

✔ 最佳答案

(1)
(i)
C3H8 + 5O2 → 3CO2 + 4H2O
2C4H10 + 13O2 → 8CO2 + 10H2O

(ii)(a)
Mass of C3H8 = 1000 x (1 - 70%) = 300g

(ii)(b)
No. of moles of C3H8 = 300/(12x3 + 8) = 6.818 mol
No. of moles of C4H8 = (1000 - 300)/(12x4 + 10) = 12.069mol
No. of moles of CO2 formed = 6.818 x 3 + 12.069 x 4 = 68.73 mol
Mass of CO2 formed = 68.73 x (12 + 16x2) = 3024g

(ii)(c)
No. of moles of O2 needed = 6.818 x 5 + 12.069 x (13/2) = 112.54 mol
Mass of O2 needed = 112.54 x (16x2) = 3601 g

(2)
Petroleum is a non-renewable fuel, and it will be used up soon.
Burning petroleum causes air pollution, and conserve petroleum can thus reduceair pollution.

(i)
bitumen
It can be used for road surfacing.

(3)
(i)
It is methane.

(ii)
CH4 + 2O2 → CO2 + 2H2O

(4)
The blue litmus solution turn red.
CO2 + H2O → H2CO3

參考: 胡雪

👍 0 👎 0