Do you consider this a challenging chemistry problem?

archcommus

Diamond Member
Sep 14, 2003
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It only involves basic ideas and concepts (as in, the first few chapters of any chemistry book), but I still think it's a bit beasty of a problem. The professor disagreed and was surprised so few people in the class got it right. Do you consider this hard for introductory chemistry?

Problem: Consider a 2.1 L, V6 engine that uses gasoline with a chemical makeup of C8H18 (density = .899 g/mL) that, when combusted, produces gases at 450 deg. C and at 1 atm pressure. Using this information, how many microliters of gasoline should be injected into EACH cylnder so that, when combusted, each piston will be fully but not overly extended?
 

Vegitto

Diamond Member
May 3, 2005
5,234
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Originally posted by: archcommus
It only involves basic ideas and concepts (as in, the first few chapters of any chemistry book), but I still think it's a bit beasty of a problem. The professor disagreed and was surprised so few people in the class got it right. Do you consider this hard for introductory chemistry?

Problem: Consider a 2.1 L, V6 engine that uses gasoline with a chemical makeup of C8H18 (density = .899 g/mL) that, when combusted, produces gases at 450 deg. C and at 1 atm pressure. Using this information, how many microliters of gasoline should be injected into EACH cylnder so that, when combusted, each piston will be fully but not overly extended?

Would be a piece of cake if I knew what 1 atm was.. Could you give me 1 atm in Pa or bar?
 

KLin

Lifer
Feb 29, 2000
30,449
752
126
Originally posted by: Vegitto
Originally posted by: archcommus
It only involves basic ideas and concepts (as in, the first few chapters of any chemistry book), but I still think it's a bit beasty of a problem. The professor disagreed and was surprised so few people in the class got it right. Do you consider this hard for introductory chemistry?

Problem: Consider a 2.1 L, V6 engine that uses gasoline with a chemical makeup of C8H18 (density = .899 g/mL) that, when combusted, produces gases at 450 deg. C and at 1 atm pressure. Using this information, how many microliters of gasoline should be injected into EACH cylnder so that, when combusted, each piston will be fully but not overly extended?

Would be a piece of cake if I knew what 1 atm was.. Could you give me 1 atm in Pa or bar?

google conversion
 

Vegitto

Diamond Member
May 3, 2005
5,234
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Originally posted by: KLin
Originally posted by: Vegitto
Originally posted by: archcommus
It only involves basic ideas and concepts (as in, the first few chapters of any chemistry book), but I still think it's a bit beasty of a problem. The professor disagreed and was surprised so few people in the class got it right. Do you consider this hard for introductory chemistry?

Problem: Consider a 2.1 L, V6 engine that uses gasoline with a chemical makeup of C8H18 (density = .899 g/mL) that, when combusted, produces gases at 450 deg. C and at 1 atm pressure. Using this information, how many microliters of gasoline should be injected into EACH cylnder so that, when combusted, each piston will be fully but not overly extended?

Would be a piece of cake if I knew what 1 atm was.. Could you give me 1 atm in Pa or bar?

google conversion

Goddamn, I have no idea of the length of one piston.. I don't think I can do it.. :(
EDIT: Weight of one piston would be handy, too.
This isn't just chemistry...
 

simms

Diamond Member
Sep 21, 2001
8,211
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0
Originally posted by: Vegitto
Originally posted by: archcommus
It only involves basic ideas and concepts (as in, the first few chapters of any chemistry book), but I still think it's a bit beasty of a problem. The professor disagreed and was surprised so few people in the class got it right. Do you consider this hard for introductory chemistry?

Problem: Consider a 2.1 L, V6 engine that uses gasoline with a chemical makeup of C8H18 (density = .899 g/mL) that, when combusted, produces gases at 450 deg. C and at 1 atm pressure. Using this information, how many microliters of gasoline should be injected into EACH cylnder so that, when combusted, each piston will be fully but not overly extended?

Would be a piece of cake if I knew what 1 atm was.. Could you give me 1 atm in Pa or bar?

101325pa
1.01325bar
 

SVT Cobra

Lifer
Mar 29, 2005
13,264
2
0
its easy just use conversion factors

plus you need to know what combustion of a hydrocarbon is going to produce...set up the equation, balance it, then set up your conversion factors
 

Armitage

Banned
Feb 23, 2001
8,086
0
0
Originally posted by: Fenixgoon
i can't do it :p

don't you need to know the length of a full extension?

No - you just need the volume of the cylinder when fully extended. You know the total displacement, and you know the number of cylinders.
 

SilentZero

Diamond Member
Apr 8, 2003
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Originally posted by: Indolent
Originally posted by: Mark R
.



You dont' need it


when combusted, produces gases at 450 deg. C and at 1 atm pressure

that's all you need. It's not realistic but is probably done to simplify the problem

I wasn't a chem major or minor for that matter, but isn't it easier to convert 1 atm to torr's and solve?
 

archcommus

Diamond Member
Sep 14, 2003
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76
The answer is 44 microliters/cylinder for anyone trying to figure it out.

And you don't need to convert pressure.
 

SaturnX

Diamond Member
Jul 16, 2000
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well with a quick calculation, I got 44 mL, not microlitres.... took about 2 lines to calculate, but I definately don't see this as being a difficult question.

--Mark
 

archcommus

Diamond Member
Sep 14, 2003
8,115
0
76
Originally posted by: SaturnX
well with a quick calculation, I got 44 mL, not microlitres.... took about 2 lines to calculate, but I definately don't see this as being a difficult question.

--Mark
Well obviously it takes more work than that as that's the wrong answer.

I also don't see it as THAT bad. I got it right but was slightly surprised I did.