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Biology; Chemistry; Physics: Post your doubts here!

peacce

peacce

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Mahnoorfatima said:
Look. First you should know that while drawing an ester you need to remove OH from carboxylic acid and H from OH group of Alcohol.
Second, Draw the Acid and then the alcohol BUT first make the mirror image of alcohol. Like if you have e.g. C-C-O (this is the alcohol having H's and removed H)
So continue the carboxylic acid joing O and then writing C.. Like Carboxylic acid with removed OH - O-C-C-H
Hopefully you got it. :/
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il aply ds in undrstndng n vil let u know :D
 
ciesgetoveralready

ciesgetoveralready

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peacce said:
Yes :(
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The General Formula for Alcohols is CnH2n+1OH
The General Formula for Carboxylic Acids is CnH2n+1COOH

Propanol is C3H7OH
Propaonic Acid will be C2H5COOH ( Note that there are total 3 carbons and 6 hydrogens in total just like how its supposed to be)

Propanol C3H7OH + Propanoic Acid C2H5COOH ----> Propyl Propanoate C2H5COOHC3H7 + water H2O

Now If you know the formula for the alcohol and carboxylic acid you're using to make an ester , then its easy. Write down the carboxylixacid first as it is like C2H5COO in this case and add the alcohol which is C3H7. Hence you get C2H5COOC3H7.
 
peacce

peacce

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ciesgetoveralready said:
The General Formula for Alcohols is CnH2n+1OH
The General Formula for Carboxylic Acids is CnH2n+1COOH

Propanol is C3H7OH
Propaonic Acid will be C2H5COOH ( Note that there are total 3 carbons and 6 hydrogens in total just like how its supposed to be)

Propanol C3H7OH + Propanoic Acid C2H5COOH ----> Propyl Propanoate C2H5COOHC3H7 + water H2O

Now If you know the formula for the alcohol and carboxylic acid you're using to make an ester , then its easy. Write down the carboxylixacid first as it is like C2H5COOH in this case and add the alcohol which is C3H7. Hence you get C2H5COOHC3H7.
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i seeee :)
 
Uchiha-Sasuke

Uchiha-Sasuke

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Mahnoorfatima said:
But what if the H isn't 2? Sorry but I need to get this!:/
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Theres ALWAYS a CH2 group difference so CxHy will ALWAYS be 14 hence H will be twice of C.. the two types are :
e.g 1) CxHy = 128
x will be 8 H will be 16
e.g 2) H2NCxHyCOOH = 145
CxHy= 145 - (mass of H2NCOOH)
x=6 H=12
ALWAYS divide by 14 when it comes to CxHy
we even use this technique to find number of carbon atoms
Mahnoorfatima said:
WHYYYY FOURTEEEEN!! WHY NOT 13! THE MR OF CH is 13 NO??? :'(
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*CH2 sorry my bad .. It's CH2
peacce said:
ciesgetoveralready can u explain me dis too? http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s07_qp_4.pdf q.8 part l.. this has ben askd before but i dint get it
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peacce said:
why 90.
and how did u get 118:eek: [USER=82593]Uchiha-Sasuke[/USER]
Click to expand...
only CxHy is unknown
COOH COOH
2(12+16+16+1)=90
118 was calculated in park k :
Mr = mass/mol
1.51/0.0128=117.9 (rounded to 118 )
 
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