(a) CH3CH2CH2CH3 reacting with Cl2 in the presence of UV light
CH3CH2CH2CH3 + Cl2 --> CH3CH(Cl)CH(Cl)CH3
Free radical substitution, so product is 2,3-dichlorobutane.

(b) CH3CH(CH3)CH3 reacting with Cl2 in the presence of UV light
CH3CH2CH2CH3 + Cl2 --> CH3CH(Cl)CH(Cl)CH3
Free radical substitution, so product is 2,3-dichlorobutane.

Are you sure that's right because it looks like addition rather than substitution?

Isn't it just:

CH_3CH_2CH_2CH_3 \ + \ Cl_2 \ \rightarrow \ HCl \ + \ C_4H_9Cl

Reply 27

Christophicus

endeavour

Are you sure that's right because it looks like addition rather than substitution?

Isn't it just:

CH_3CH_2CH_2CH_3 \ + \ Cl_2 \ \rightarrow \ HCl \ + \ C_4H_9Cl

oh yeah, i always get mixed up.
It's my own fault for trying to answer too many questions. I was doing chemistry all day when I typed that.

Reply 28

perkyDani

Question-
on a mark scheme, it says u can dehydrate ethanol to form ethene- what conditions are needed? and can this happen to all alcohols (does it depent on whether they are primary, secondary or tertiary??

Reply 29

Christophicus

perkyDani

Primary alcohol: CH3CH2OH ---> CH2=CH2 + H2O
Secondary alcohol: CH3CH(OH)CH3 --> CH3CH=CH2 + H2O
Tertiary alcohol: (CH3)2C(OH)CH3 --> (CH3)2C=CH2 + H2O

Primary and secondary alcohols
Reagent: Concentrated H2SO4
Conditions: Heat (under reflux)

Tertiary alcohols
Reagent: None
Conditions: Heat (under reflux)

Reply 30

Abbas6

Hi

How would you draw the structural formula for Buta-1,3-diene . I've had a stab at it, but I have a feeling it's wrong. Diene means two double bonds right? :confused:

untitled.JPG8.5KB

Reply 31

Christophicus

abbasi

Hi

How would you draw the structural formula for Buta-1,3-diene . I've had a stab at it, but I have a feeling it's wrong. Diene means two double bonds right? :confused:

yep that's right, see attached (this is how I'd draw it)
My edexcel book says it's CH2=CHCH=CH3 but is clearly wrong. How can you have 5 bonds on a carbon atom?

buta.gif0.6KB

Reply 32

Abbas6

Widowmaker

yep that's right, see attached (this is how I'd draw it)
My edexcel book says it's CH2=CHCH=CH3 but is clearly wrong. How can you have 5 bonds on a carbon atom?

Thanks Widowmaker. Your diagram is a lot more clearer than mine! :smile:

And you're right about CH2=CHCH=CH3. That would appear to be wrong (the last Carbon having 5 bonds).

Reply 33

Mustard-man

hello people, this may seem like a stupid question, but how do you know which way the arrows go in a hess cycle.

thanks

Reply 34

Christophicus

gordon2002

hello people, this may seem like a stupid question, but how do you know which way the arrows go in a hess cycle.

thanks

depends on whether you're using enthalpy of formation/enthalpy of combustion values

Reply 35

meawinner1

*girlie*

Does anybody have any organic chemistry revision notes??? We just practically missed all the organic bits out...my teacher is soo crap.

Go here http://www.wbateman.demon.co.uk/asa2sums/sum2.2/sum2.2.htm

Reply 36

raam001584

this is a unit 1 question ( couldnt find forum for this thread)

why do melting points differ between simple molecular subtances , which are bonded by van der waals?

in some books it says due to increase atom size and thus nuclear charge. but in other books and in 1 mark scheme it says, the greater number of electrons the more stronger van der waals therefore greater melting pt

could some1 clear this point up plz