Strange, strange prac/research task...molar heat of combustion...sort of...PLZ HELP!! (1 Viewer)

[doomedstudent]

Hi, i have a research task in which you have to assess which of four given alcohols would (best) keep you alive for four days if u only had one litre of each...

you have to account for the Molar heat of combustion, the amount of CO2 gas produced, and weather it combusts completely (ie how much Carbon Monoxide will be produced)

The four alcohols are:

• Methanol
• 1-Propanol
• 3-Pentanol
• 1-Hexanol

I have a good idea about how to do the actual task, but i REALLY need facts, they are impossible to find. Mainly just the Molar heat of combustion (or just heat of combustion), and the amount of CO2.

Any help gladly appreciated!!

 

[Riviet]

Lol, a very interesting question. I think the heat combustion increases as the molecule gets larger ie hexanol would have the highest heat combustion followed by pentanol but i'm not sure if this is true for alkanols. The problem is each of the alcohols is probably better off in one of the categories you mentioned so it will be hard to find a clear winner of the 4. I guess that's why you were asked to "assess" them and i hate that word for a good reason in the hsc.

 

[Dreamerish*~]

Yes, the molar heat of combustion increases with molecular mass.

You can compare the amount of CO₂ produced by writing equations, assuming they're undergoing complete combustion. For example:

CH₄ + O₂ → CO₂ + 2H₂O

Whether or not it combusts completely depends on the reaction conditions. Complete combustion takes place when the reaction occurs in excess oxygen.

 

[doomedstudent]

hmm

Yea i figured as much that it gets bigger as you go along. thanks for the equation bit i completely forgot about doing that. do u have any idea where i can get the actual data for the heat of combustion? im all out of ideas, all i can think of is to but a data book....

 

[Dreamerish*~]

It is quite a strange task. You need to know how to calculate the molar heat of combustion of fuels, but the "keep you alive for 4 days" goes a little too far.

Don't worry about it too much. Of course, if you can get your hands on a data book, then do so.

 

[insert-username]

From another thread, I found these two molar heats of combustion. It's a start, at least:

Methanol 726kJ/mol
1-propanol 2101kJ/mol


I_F

 

[doomedstudent]

Thanks for those two, that is a start. yea i think im gunna try and "borrow" my chem teachers data book. or he might even let me who knows. such a strange task...

 

[Riviet]

You could probably say any of them would last longest, as long as you back up your opinion with relevant info. Just an idea.

 

[doomedstudent]

I found it!! i got all the info on molar heat of combustion!! so stoked. but it says that while methanol, 1-propanol and 3-pentanol release consecutively more heat, 1-hexanol releases less than 3-pentanol rather confusing but ill run with it. Any idea how much heat it takes to raise the temperature of the environment?? LOL.

 

[jamesy_1988]

I have a copy of the heat of combustion prac on my website

http://www.geocities.com/jamesyscience_chemistry

Then just navigate to the production of materials practicals

Hope it helps

Jamesy

 

[Riviet]

I had a look at it just then, and it's very comprehensive and well set out.

 

[pLuvia]

I have a similar assessment except we, worth 15% of the final hsc mark

Determine the relations ship between the length of carbon chain and the heat of combustion of alcohols

we're only using methanol, ethanol and 1-propanol

 

[doomedstudent]

cheers

thanks for that site, im checking it out now.