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Chemistry: Post your doubts here!

chocolate_girl

chocolate_girl

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  1. understand, in simple terms, the concept of electronegativity
    and apply it to explain the properties of molecules such as bond polarity (3h), the dipole moments of molecules (3j), the behaviour of oxides with water (3.1j) and the acidities of chlorine-substituted ethanoic acids (10.6c)

    Please explain me the last chlorine substituted ethanoic acid part someone
 
sidbloom1995

sidbloom1995

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Anzuman turin said:
help plzz

9701.mj.06 q, 25
9701.on.06 q,37,3
9701.mj.01 q 34,26,
9701.on.07 q 33,37,4
9701.mj.08 q 27 ,
9701.on.09 ( varient 11) 28,24,21
9701.on.10(varient 12) 39,27,13
9791.0n.10 (varient 11) q 38 ( what product will form if tollen reagent react with it ),35,29
9701.mj.10 (varient 11) q 12,
9701.mj.11(varient 12) q 38,29,28,24,11,
*9701.mj.11(varient 11) q 36,27,34,26,16
9701.on.11.(varient 12) q 9
9701.on.11 (varient 11) q 27,29,21,
9701.mj.12, (varient 12) q 24,23
9701.mj.12 (varient 11) q 29,23,22,9,
9701.on.12 (varient 11) q 26,
Click to expand...
m/j 2011 v.12
Q12 answer is C check the pics for explanation
Q 24 answer is C the answer is in pics
 

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chocolate_girl

chocolate_girl

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TheStallion-Reborn said:
Can someone please tell me what are 'dipole forces'
Click to expand...
Those forces that exist between dipoles, a type of molecular force
e.g. H--Cl molecule Cl gets partial negative charge and H gets partial positive charge hence H(partial positive) of one HCl is attracted towards Cl(partial negative) of the other HCl molecule
 
sidbloom1995

sidbloom1995

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Anzuman turin said:
help plzz

9701.mj.06 q, 25
9701.on.06 q,37,3
9701.mj.01 q 34,26,
9701.on.07 q 33,37,4
9701.mj.08 q 27 ,
9701.on.09 ( varient 11) 28,24,21
9701.on.10(varient 12) 39,27,13
9791.0n.10 (varient 11) q 38 ( what product will form if tollen reagent react with it ),35,29
9701.mj.10 (varient 11) q 12,
9701.mj.11(varient 12) q 38,29,28,24,11,
*9701.mj.11(varient 11) q 36,27,34,26,16
9701.on.11.(varient 12) q 9
9701.on.11 (varient 11) q 27,29,21,
9701.mj.12, (varient 12) q 24,23
9701.mj.12 (varient 11) q 29,23,22,9,
9701.on.12 (varient 11) q 26,
Click to expand...

Q28. the general equation for empirical formula (e.f) and molecular formula (m.f) is
(m.f) = n(e.f)
where n is a whole number
we have the emperical formula of our acid formed as
C4H8O2
form this we can tell the minimum number of O can be only one and that will only be if we divide it by 2
so [C4H8O2]]/2 = C2H4O
thus this is our answer, C

Q29. im sorry i dont know this one!

Q37. A
we can react C2H4 with H2 at 200*C over the Ni catalyst to get CH3CH3
we can simply polymerize CH2=CH2
we can simply react CH2=CH2 with KMnO4 to get (OH)HC-CH(OH)
so all of them react in a single step to form the given product!

Q38. D
well in this one to be honest i didnt see the 3 choice as the 2 was wrong so the answer is D, only 1
2 is wrong because when we oxidise an alcohol the final product is -CO2H and since we already have a -CO2H group attached to the chiral C* we will not get a C*

m/j 2011 v.11
Q16. this answer is something im not sure of or i dont have any book evidence but it is the logic i used to get my answer so i could be wrong
definition of oxidation is loss of electron, loss of H+
a stronger oxidizing agent will be one that does not donate an H+ to the [Cl-] and [I-] solutions
with H2PO4 white acidic gas was formed, being HCl
were as with H2SO4, with iodine, purple fumes of gas were formed, being I2, meaning [I-] did not receive a H+ and thus was more strongly oxidized then with H2PO4

Q26. im sorry i dont know this one's explanation

Q27. D sodium ethanoate is simply CH3COO-Na+
so look for the ester which form CH3COOH on hydrolysis,
in an ester the C with C=O and the rest of the chain behind it belongs to the acid!
only in D does our chain matches the formula CH3COOH
so D is ou answer!

Q34. NaCl is a salt and cannot give an alkaline solution on dissolving so it is wrong
MgCl2 is slightly hydrolysed by water so it is slightly acidi
AlCl3 is readily hydrolysed and give HCl which is acidic
thus the answer is B

Q36. D
because 2 is wrong, it does not react readily with H2 gas
 
Hassan Ali Abid

Hassan Ali Abid

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chocolate_girl said:
  1. understand, in simple terms, the concept of electronegativity
    and apply it to explain the properties of molecules such as bond polarity (3h), the dipole moments of molecules (3j), the behaviour of oxides with water (3.1j) and the acidities of chlorine-substituted ethanoic acids (10.6c)

    Please explain me the last chlorine substituted ethanoic acid part someone
Click to expand...

The concept of electronegativity, bond polarity and diapoles are related to AS....its in (shapes and bonding ch..CH4) , the behaviour of oxides with water is the topic of AS inorganic and the and the acidities of chlorine-substituted ethanoic acids falls under A2 organic...

chlorine substituted ethanoic acid are mono chloroethonic acid and di or tri chloroethanoic acid .... C-Cl3-CooH , Cl-CH2-Cooh etc etc .....under this topic u have to explain the effect of chlorine on the strength of acids.... just have a look on m/j 12 (42) ..there's a question about it ...if you'll see that maybe then you'll have a better idea of that .
 
chocolate_girl

chocolate_girl

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Hassan Ali Abid said:
The concept of electronegativity, bond polarity and diapoles are related to AS....its in (shapes and bonding ch..CH4) , the behaviour of oxides with water is the topic of AS inorganic and the and the acidities of chlorine-substituted ethanoic acids falls under A2 organic...

chlorine substituted ethanoic acid are mono chloroethonic acid and di or tri chloroethanoic acid .... C-Cl3-CooH , Cl-CH2-Cooh etc etc .....under this topic u have to explain the effect of chlorine on the strength of acids.... just have a look on m/j 12 (42) ..there's a question about it ...if you'll see that maybe then you'll have a better idea of that .
Click to expand...

Emm im an AS level student and i also thought that this part isnt in the syllabus but the cie official syllabus says it is although i hvnt met anysuch questions in past papers so far

Can u please tell me if any of these syllabus contents are included in the AS level

1)describe the formation of carboxylic acids from nitriles
2)describe the reactions of carboxylic acids in the formation of acyl chloride
3)describe the formation of amides from the reaction between RNH2 and R'COCl
4)describe amide hydrolysis on treatment with aqueous alkali or acid
 
S

sitooon

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what does this point mean in Ms " line is a continuous curve of best fit that does not deviate to accommodate an off curve point. " ?
 
Hassan Ali Abid

Hassan Ali Abid

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chocolate_girl said:
Emm im an AS level student and i also thought that this part isnt in the syllabus but the cie official syllabus says it is although i hvnt met anysuch questions in past papers so far

Can u please tell me if any of these syllabus contents are included in the AS level

1)describe the formation of carboxylic acids from nitriles
2)describe the reactions of carboxylic acids in the formation of acyl chloride
3)describe the formation of amides from the reaction between RNH2 and R'COCl
4)describe amide hydrolysis on treatment with aqueous alkali or acid
Click to expand...


1. Yes its in the AS topic ... Acid hydrolysis of nitriles produces carboxylic acid ...do learn its conditions and reagents.
2. Its an an topic ...u dont need to know about it
3 and 4. They falls under A2 organic.

* You should know about the reduction of nitriles (This equ is of both AS and A2..).
 
daredevil

daredevil

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sitooon said:
what does this point mean in Ms " line is a continuous curve of best fit that does not deviate to accommodate an off curve point. " ?
Click to expand...
basically that u have to make a straight best fit line... leaving out the points that don't fal on the line
 
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