Chemistry Questions to do with cars/petrol/engines.?

Question

1 - How are poisonous oxides of nitrogen formed in a car engine?

2- Lead compounds are added to petrol to improve its efficiency why/how does this cause pollution problems?

3- How can pollution caused by lead additives in petrol be removed?

4- Carbon and carbon monoxide are pollutants formed by inefficient combustion of petrol - how could the efficiency be improved?

Answer 1

1 - The combustion is so hot that nitrogen of the air reacts with oxygen to form oxides. Because there are a few different oxides formed, they're collectively called NOx.


2 - Lead bromide vapors are spewed out in the exhaust. Tetraethyllead, Pb(C2H5)4, is one additive. But if that alone were used, lead deposits would gum up the engine. So ethylene bromide, Br-CH2CH2-Br, is added to form PbBr2 vapor.

3 - One can only stop using lead additives. This can be expensive, because the alternative is to process gasolines more intensively to increase the amount of branched-chain hydrocarbons and aromatic (benzene, toluene, xylenes) hydrocarbons. I can imagine that lead additives are still used in some poorer parts of the world.

4 - Catalytic converters remove these pollutants, but converters do nothing for engine efficiency. One can only use a good grade of petrol and keep the engine in tune. Make sure the carbeurator is well adjusted.

Answer 2

Damn! I'm doing your homework here dude!!!

I'm not going to give you answers for Q's 1 to 3 as they have already been answered very well by other people here. However, I'll give you an answer for Q4.

4- Carbon and carbon monoxide are pollutants formed by inefficient combustion of petrol - how could the efficiency be improved?

Cars with fuel injection systems rather than carburetter. A car with a good electronic ignition system, will produce a more clean exhaust gasses (ideally CO2 and Water) as it will usually have a Lambda (Oxygen) sensor and a CO sensor in the exhaust. This information will then be relayed back the the ECU (A computer controlling the injection system), which will then adjust the Fuel/Air mixture to try and give more complete combustion.

The result? More MPG. Cleaner Exhaust Gasses.

Answer 3

1 - How are poisonous oxides of nitrogen formed in a car engine?

Mainly nitrogen oxide is only formed in areas of large energy, such as lighting, or in the this case, sparking battery.

2- Lead compounds are added to petrol to improve its efficiency why/how does this cause pollution problems?

lead in petrol caused the largest source of exposure to lead, a heavy metal which can bloke enzymes and effect the nervous system...which we need to function
It led to several cases of neuropsychiatric disease

3- How can pollution caused by lead additives in petrol be removed?

By removing the lead and have other additives to increase the octane number.

However lead has the effect of poisiong platinum catalyse by sticking to it, so i guess that would work as well.

4- Carbon and carbon monoxide are pollutants formed by inefficient combustion of petrol - how could the efficiency be improved?

1. A turbo charger which will force more air into the chamber. This would provide oxygen, which equals better combustion.

Answer 4

1 catalytic converters give off sulphides, (the egg smell)

2 most petrol engines now use unleaded fuel

3 see answer2

4 burning petrol (a hydrocarbon) is always going to give off carbon gases. and the petrol engine is only about 45% efficient at best. needs a new design or fuel!

hope this helps

Answer 5

1. When burned at very high temperatures and pressure (such as in a car engine) the fuel produces NO2 as a by product.
2. Lead is extremely toxic and when burned!
3. Using unleaded petroleum
4. Greater air intake to the engine!

Answer 6

I kinda get the jello, I can even put up with the ice, but why not hand cuffs or soft cotton cord? Dallas Oh wait this was Chemistry not Physics.