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#### 109270

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##### Organic hydrocarbon assignment help
« on: October 19, 2008, 05:09:10 AM »
1. An organic substance consisting of exlusively carbon, hydrogen, ozygen was completely burnt in excess oxygen to produce 24.91g of CO2 and 10.2g of H2O. If 11.563g of the initial substance was burnt what was the empirical formula of the substance?
my answer was = C5 H10 O2

2. If 102g of this substance burnt completely with 6.5mol of oxygen what is the molecular formula of this substance?

3. A separate sample of this substance was taken and reduced, a process which removed all oxygen atoms. What is the molecular formula for the hydrocarbon produced?

I am having a lot of trouble with the second 2 questions, if anyone can help me please do so.
Thanks

#### Astrokel

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##### Re: Organic hydrocarbon assignment help
« Reply #1 on: October 19, 2008, 09:04:34 AM »
hey 109270, your 1 is correct.

2.what is the stoichiometric ratio of the substance to oxgen in the reaction?
If there is 6.5mol of oxygen, how many moles of the substance is there?
Are you able to calculate the Mr, thus the molecular formula?

As for 3, it will just be your molecular formula without the oxygen atoms, have you heard of deoxygenation?
No matters what results are waiting for us, it's nothing but the DESTINY!!!!!!!!!!!!

#### 109270

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##### Re: Organic hydrocarbon assignment help
« Reply #2 on: October 19, 2008, 09:31:14 AM »
thanks you, erm no i havent.
i have some more questions which are also hurting my head.

For an organic compound with the empirical formula of C2H3Br provide an example of two types of geometric isomers, including a structural diagram and IUPAC name for each.

I only have one of the two.

#### sjb

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##### Re: Organic hydrocarbon assignment help
« Reply #3 on: October 19, 2008, 09:33:28 AM »
As for 3, it will just be your molecular formula without the oxygen atoms, have you heard of deoxygenation?

Not really, don't forget to fill the valences back up (IMO), so deoxygenation of acetone (propanone) CH3C=OCH3 will not give CH3CC3, but CH3CH2CH3 instead.

So I don't think that the part of the question is that well defined, because deoxygenation of acetone should yield propane, but by a similar argument deoxygenation of the enol of acetone (CH3CH(OH)=CH2) may yield propene. I don't see how you can tell the difference as they both (the ketone and the enol) have formulae C3H6O...

Just a thought

S

(edit wrong formula)
« Last Edit: October 19, 2008, 10:03:28 AM by sjb »

#### Astrokel

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##### Re: Organic hydrocarbon assignment help
« Reply #4 on: October 19, 2008, 09:51:49 AM »
As for 3, it will just be your molecular formula without the oxygen atoms, have you heard of deoxygenation?

Not really, don't forget to fill the valences back up (IMO), so deoxygenation of acetone (propanone) CH3C=OCH3 will not give CH3CC3, but CH3CH2CH3 instead.

So I don't think that the part of the question is that well defined, because deoxygenation of acetone should yield propane, but by a similar argument deoxygenation of the enol of acetone (CH3CH(OH)=CH3) may yield propene. I don't see how you can tell the difference as they both (the ketone and the enol) have formulae C3H6O...

Just a thought

S

hi sjb, thanks for pointing it out! I'm aware of that and because i thought it was a high school chemistry and since the compound was not specified either.
No matters what results are waiting for us, it's nothing but the DESTINY!!!!!!!!!!!!

#### 109270

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##### Re: Organic hydrocarbon assignment help
« Reply #5 on: October 19, 2008, 10:02:11 AM »
Yes it is highschool chemistry, that question is on my assignment. I wrote it exactly as it is written on the sheet.
Can anyone help me more specifically?

#### Astrokel

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##### Re: Organic hydrocarbon assignment help
« Reply #6 on: October 19, 2008, 10:14:21 AM »
Quote
For an organic compound with the empirical formula of C2H3Br provide an example of two types of geometric isomers, including a structural diagram and IUPAC name for each.

I only have one of the two.

Could you post your work here?
No matters what results are waiting for us, it's nothing but the DESTINY!!!!!!!!!!!!