Organic Chemistry Question-Cycloalkanes

[agm06002]

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Hi,

I was wondering if somebody could help me out with these questions for my Organic Chemistry class.

I would greatly appreciate it!

FIRST QUESTION: The general molecular formula for alkanes is Cn H2n+2. What is the general molecular formula for:

D.) Cyclic hydrocarbons that contain one double bond

SECOND QUESTION: A certain hydrocarbon has a molecular formula of C5 H8. Which of the following is not a structural possibility for this hydrocarbon:

A.) It is a cycloalkane

B.) It contains one ring and one double bond

C.) It contains two double bonds and no rings

D.) It is an alkyne

I would appreciate it if somebody could explain how they were able to do these problems!

Many Thanks,

Andrew🙂

 

[JesperIt]

Hi,

I was wondering if somebody could help me out with these questions for my Organic Chemistry class.

I would greatly appreciate it!

FIRST QUESTION: The general molecular formula for alkanes is Cn H2n+2. What is the general molecular formula for:

D.) Cyclic hydrocarbons that contain one double bond

Read up on your degrees of unsaturations of hydrocarbons. This concept will play a crucial role later when you learn specstroscopy. But for now, each pi bond is one degree of unsaturation and each ring is another. To see this, take the simple case of propane. (Why propane?) It has the molecular formula of C3H8 right? Now add double bond...it is now propene which is C3H6 right? Now add another double bond to make it linear or 1,2-prop-di-ene and you get C3H4 right? Or instead make it one triple bond, or propyne and you have C3H4 as well. Instead, now lets do a ring and get cyclopropane and we have C3H6. Add a double bond to that and we have C3H4 or cyclopropene. Can you see a pattern?

Alkane is CnH2n+2

One pi bond or One ring is CnH2n

Two pi bond or One ring and a pi bond is CnH2n-2

Hope I am right, I just woke up from my nap.

Apply this to question below as well.



SECOND QUESTION: A certain hydrocarbon has a molecular formula of C5 H8. Which of the following is not a structural possibility for this hydrocarbon:

Saturated it would be C5H12. So we have 12H-8H = 4H divide by 2 we have 2 degrees of unsaturation. Thus we can have 2 pi bonds, or 1 pi bond and a ring or whatever combo you can think of that follows the rule.



A.) It is a cycloalkane
1 ring, well lets think....


B.) It contains one ring and one double bond
1 pi bond and one ring works


C.) It contains two double bonds and no rings
2 pi bonds, this works (no rings)


D.) It is an alkyne
2 pi bonds, this works.


I would appreciate it if somebody could explain how they were able to do these problems!

Many Thanks,

Andrew🙂

Hope that helps. Oh and know what a double bond and triple bond is. Double has a sigma and 1 pi bond, triple is sigma and 2 pi bonds. That stuff is on MCATs too.

 

[tdjn]

My god, good luck with your OChem class in the future... Just to warn you, it gets a lot harder than figuring how many hydrogens are in a cyclic compound.

Instead of asking answers for hw online, I suggest you start pulling a little weight on your own.

 

[agm06002]

Tdjn,

Yes, I am pulling my own weight. This summer I studied OChem on my own and learned about the first 4 / 5 chapters of the textbook that I'm currently using and I'm doing very well in the class right now.

I use the service to brush up on some techniques and as an extra resource!

Andrew

 

[JesperIt]

Tdjn,

Yes, I am pulling my own weight. This summer I studied OChem on my own and learned about the first 4 / 5 chapters of the textbook that I'm currently using and I'm doing very well in the class right now.

I use the service to brush up on some techniques and as an extra resource!

Andrew

You said OChem...you must be from the west coast...all the east coast folks call it Orgo. Okay maybe a bit of an exaggeration, but it does seem like it to me.

 

[tdjn]

Tdjn,

Yes, I am pulling my own weight. This summer I studied OChem on my own and learned about the first 4 / 5 chapters of the textbook that I'm currently using and I'm doing very well in the class right now.

I use the service to brush up on some techniques and as an extra resource!

Andrew

Fair enough. Good luck with your OChem class in the future.

You said OChem...you must be from the west coast...all the east coast folks call it Orgo. Okay maybe a bit of an exaggeration, but it does seem like it to me.

Hah, I actually go to a school in the midwest. And I can't stand it when people call it "Orgo" 🙂

 

[agm06002]

I'm attending a school in Connecticut (University of Connecticut - Greater Hartford Campus)

I picked up on the name "OChem" from the previous post.

I like the name Orgo personally. 😎

Andrew

 

[JesperIt]

I'm attending a school in Connecticut (University of Connecticut - Greater Hartford Campus)

I picked up on the name "OChem" from the previous post.

I like the name Orgo personally. 😎

Andrew

I detest the use of the word "Orgo". When I use OChem on the East, the students there do not know what I am saying thus I use the words Organic Chem instead. But to each his own. Some people on the East think USC is South Carolina while those on the West know it for Southern California. I have given up on educating people about areas outside their sphere of influences.

 

[tdjn]

Agreed 🙂

 

[chad5871]

I personally hate (*HATE*) when people say Orgo or OChem. I always say Organic. Yes, it's three syllables, but it sounds so much more proper.

 

[JesperIt]

I personally hate (*HATE*) when people say Orgo or OChem. I always say Organic. Yes, it's three syllables, but it sounds so much more proper.

If you are talking proper then you should be saying "Organic Chemistry" since Organic spoken can have another connotation (e.g. Organic foods). While you are at it, let us forget about calling it Gen Chem or Chem or Chemistry or Inorganic Chem and call it General Chemistry. Though Inorganic Chemistry is itself another discipline when we move to upper division and graduate levels. And no more P Chem and call it Physical Chemistry....and the list goes on...Synthetic, Analytical, Biochemistry...yadda yadda

Point is (if there even really is one) we have Gen Chem, P Chem, and O Chem...where the **** does Orgo come from? Orgy? Why not Orga?

 

[pingouin]

SDN is not to be used for homework help. Closing.