as level chemistry; alkanes and alkenes helpp!!!

hi guys, im really stuck and dumb at chemistry :/
can you please help me on this question:

bromine reacts with both ethane and ethene
i) write the equation for the reactions below
ethane + bromine
ethene + bromine

ii) classify the 2 reactions in terms of the type of reaction occuring
ethane + bromine
ethene + bromine

thanks guys :smile:

Reply 1

hazbaz

11

Original post by Anonymous 16

hi guys, im really stuck and dumb at chemistry :/
can you please help me on this question:

bromine reacts with both ethane and ethene
i) write the equation for the reactions below
ethane + bromine
ethene + bromine

ii) classify the 2 reactions in terms of the type of reaction occuring
ethane + bromine
ethene + bromine

thanks guys :smile:

Whats the chemcial formula for ethane and Bromine, and then balance. Similarly whats the chemcial formula for Ethene and then balance. Are they exo endo etc

Reply 2

Anonymous 16

OP

Original post by hazbaz

Whats the chemcial formula for ethane and Bromine, and then balance. Similarly whats the chemcial formula for Ethene and then balance. Are they exo endo etc

ethane is C2H6 and bromine is Br2
ethene is C2H4 and bromine is Br2
what next? :s-smilie:

Reply 3

sweetascandy

18

Original post by Anonymous 16

ethane is C2H6 and bromine is Br2
ethene is C2H4 and bromine is Br2
what next? :s-smilie:

ethane one: C2H6 + Br2 --> 2CBr + 3H2
ethene one: C2H4 + Br2 --> 2CBr + 2H2

I'm probz wrong though... i really hate chemistry this year :-/

Btw, have you done polarisation?! I literally can't understand it :s-smilie:

Reply 4

Princess Bubbles

16

Original post by Anonymous 16

hi guys, im really stuck and dumb at chemistry :/
can you please help me on this question:

bromine reacts with both ethane and ethene
i) write the equation for the reactions below
ethane + bromine
ethene + bromine

ii) classify the 2 reactions in terms of the type of reaction occuring
ethane + bromine
ethene + bromine

thanks guys :smile:

Bromine water is the test for alkenes. The bromine will add across the double bond to give a disubstituted haloalkane.
Reaction with Ethene: C2H4 + Br2 = C2H4Br2
Reaction with Ethane: No reaction

Original post by sweetascandy

ethane one: C2H6 + Br2 --> 2CBr + 3H2
ethene one: C2H4 + Br2 --> 2CBr + 2H2

I'm probz wrong though... i really hate chemistry this year :-/

Btw, have you done polarisation?! I literally can't understand it :s-smilie:

That is wrong. See my answer above :smile:

Reply 5

chemkid

11

ethane
C2H6 + Br2 --> C2H4 + 2HBr
that's the overall one for the first halogenation of ethane... if you want the step by step mechanism that's different
ethene
C2H4 + Br2 --> C2H4Br2

ethane one is a free radical substitution
ethene one is an electrophilic addition reaction

Reply 6

sweetascandy

18

Original post by Seham

Bromine water is the test for alkenes. The bromine will add across the double bond to give a disubstituted haloalkane.
Reaction with Ethene: C2H4 + Br2 = C2H4Br2
Reaction with Ethane: No reaction

That is wrong. See my answer above :smile:

At least I attempted to do it... you have to give me credit for that :p:

Reply 7

chemkid

11

Original post by Seham

Bromine water is the test for alkenes. The bromine will add across the double bond to give a disubstituted haloalkane.
Reaction with Ethene: C2H4 + Br2 = C2H4Br2
Reaction with Ethane: No reaction

ethane will react with bromine provided there is UV light

Reply 8

Anonymous 16

OP

Original post by Seham

Bromine water is the test for alkenes. The bromine will add across the double bond to give a disubstituted haloalkane.
Reaction with Ethene: C2H4 + Br2 = C2H4Br2
Reaction with Ethane: No reaction

That is wrong. See my answer above :smile:

thank you soo much :smile:

how do you do part ii)?

Reply 9

Princess Bubbles

16

Original post by sweetascandy

At least I attempted to do it... you have to give me credit for that :p:

Ok

Original post by chemkid

ethane will react with bromine provided there is UV light

That was not specified, but you are correct. If UV light is provided, the product of the reaction of ethane with bromine is:
HBr + C2H5Br

Reply 10

Aristotle's' Disciple

19

Original post by sweetascandy

ethane one: C2H6 + Br2 --> 2CBr + 3H2
ethene one: C2H4 + Br2 --> 2CBr + 2H2

I'm probz wrong though... i really hate chemistry this year :-/

Btw, have you done polarisation?! I literally can't understand it :s-smilie:

Okay I'm gonna help you in a nutshell!

A polar bond is when two atoms with different levels of electronegativity join, and the covalent electons and more attracted to the more negative atom. An example is B-Cl.

Intermolecular.

Dipole-Dipole is basically the same thing. Remember this!

Van Der Waals should be easy.

Hydrogen Bonding is when H atoms bond with N, O or F atoms. ONLY THESE ONES! There must always also be a lone pair present.

P.s Please rate me if you found this helpful :smile:

Reply 11

Princess Bubbles

16

Original post by Anonymous 16

thank you soo much :smile:

how do you do part ii)?

Well you need to think about the products being formed.
The ethane one is a free-radical substitution as you are substituting one H for a Br in the ethane.
The ethene one is an electrophilic addition reaction as you are adding a molecule across a double bond.

(edited 13 years ago)

Reply 12

Princess Bubbles

16

Original post by chemkid

ethane
C2H6 + Br2 --> C2H4 + 2HBr
that's the overall one for the first halogenation of ethane... if you want the step by step mechanism that's different
ethene
C2H4 + Br2 --> C2H4Br2

ethane one is a free radical substitution
ethene one is an electrophilic addition reaction

The ethane reaction products are incorrect. You do not form ethene. You form C2H5Br + HBr.

Reply 13

sweetascandy

18

Original post by shahedul

Okay I'm gonna help you in a nutshell!

A polar bond is when two atoms with different levels of electronegativity join, and the covalent electons and more attracted to the more negative atom. An example is B-Cl.

Intermolecular.

Dipole-Dipole is basically the same thing. Remember this!

Van Der Waals should be easy.

Hydrogen Bonding is when H atoms bond with N, O or F atoms. ONLY THESE ONES! There must always also be a lone pair present.

P.s Please rate me if you found this helpful :smile:

Hmm well we havent really covered all of that yet.. we've just had an introductory lesson to it. Now I think I understand it a bit more, having had another lesson on it today. But thanks anyway! :smile:

P.S. I'll +rep you anyway for the sake of it :P

Reply 14

Chemhistorian

4

Original post by Anonymous 16

hi guys, im really stuck and dumb at chemistry :/
can you please help me on this question:

bromine reacts with both ethane and ethene
i) write the equation for the reactions below
ethane + bromine
ethene + bromine

ii) classify the 2 reactions in terms of the type of reaction occuring
ethane + bromine
ethene + bromine

thanks guys :smile:

This WILL get easier :smile:

Once you see more and more reactions of this type, you'll get to know how they work and be able to apply them...if that sounds like the impossible now, you are wrong, just practice :smile:

Sorry that wasnt answering the question, it's just because im just starting to actually learn my A2 organic/analysis module (OCR A) and what ive said holds true :smile:

Also past papers ftw :smile:

Good luck!

as level chemistry; alkanes and alkenes helpp!!!

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