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Chemistry: Post your doubts here!

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GUYSSSS. Gotta help me with this, PLEASEEE. hahahaha
Must be very easy for you guys! :cool:
Anyways, okay.
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w13_qp_13.pdf
Q27 (C)

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w13_qp_12.pdf
Q3 (B) Q8 (D) [ i guess all these answers correctly, but i dont understand why ]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_12.pdf
Q11 (A) [srsly no, what is this.]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w11_qp_12.pdf
Q24 (B) , Q26 (A), Q30 (A)

THANK YOU SO SO MUCHHHHHH!! please help :D
 
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I have only done w13 13
so
Q27
it is clearly an alcohol and a tertiary one as it is mentioned DOES NOT
Try making a tertiary alcohol WITH chiral center
so the center carbon can not be bonded to 2 CH3
the central carbon is bonded to OH,CH3,CH2CH3 and CH2CH2CH3
 
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Q8 whats the definition of enthalpy change of formation?
One mole of substance formed from its elements under standard conditions. So, its C! A and B definitely out since C in standard conditions should be in solid state.

Q10
Just look at Ca, Al and Si.
Do the empirical formula stuffs.
So, Ca= 14.04/40.1=0.35
Al= 14.17/27= 0.525
Si= 14.75/28.1=0.525
so you see, the mole ratio of Al and Si is the same, so you can straight eliminate B and D

Al and Si, both of them divided by 0.35 (cause it is the smallest mole ratio among three of them)
so 0.525/0.35=1.5
See the formula there, is Ca2 right? So, times 2. yeahhh it is 3. Hope you understand :(

Q11 it is posted somewhere like previous pages. or you just go and search google for the question. LOL SORRY trying to help but yeah, im rushing! WAIT I FOUND IT.
Moles of CO2=72/24000=0.003
moles of Al4C3= 0.003/3=0.001 (as ratio of Al4C3:CH4 is 1:3)
now mass of Al4C3= 0.001 into (27+27+27+27+12+12+12)=0.144g

Q19 idk whyyy
 
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Q8 whats the definition of enthalpy change of formation?
One mole of substance formed from its elements under standard conditions. So, its C! A and B definitely out since C in standard conditions should be in solid state.

Q10
Just look at Ca, Al and Si.
Do the empirical formula stuffs.
So, Ca= 14.04/40.1=0.35
Al= 14.17/27= 0.525
Si= 14.75/28.1=0.525
so you see, the mole ratio of Al and Si is the same, so you can straight eliminate B and D

Al and Si, both of them divided by 0.35 (cause it is the smallest mole ratio among three of them)
so 0.525/0.35=1.5
See the formula there, is Ca2 right? So, times 2. yeahhh it is 3. Hope you understand :(

Q11 it is posted somewhere like previous pages. or you just go and search google for the question. LOL SORRY trying to help but yeah, im rushing! WAIT I FOUND IT.
Moles of CO2=72/24000=0.003
moles of Al4C3= 0.003/3=0.001 (as ratio of Al4C3:CH4 is 1:3)
now mass of Al4C3= 0.001 into (27+27+27+27+12+12+12)=0.144g

Q19 idk whyyy
That helped,thanks for the effort :)
 
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Q21 The functional groups that react with Na are CO2H and OH, so three of any of these should be present in the compound. B and D are ruled out. NaOH will react with CO2H, so there should be 1 CO2H and 2 OH groups.
thanks, but i'm still confused :/
I get D is ruled out butt how C I still umm :S :/
 
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okay got a bit, but the part where yu said "but NaOH only with -CO2H so -1"
tht I didn't get :/
Na will react with both Na and COOH okay so
when it reacts with 1 OH it will give charge of -1 and then another OH it will become -2 and then with COOH it will be -3 as the question says
and NaOH will only react with COOH
so it will give -1 with one COOH thats it
but for A there are 3 OH groups and 1 COOH
 
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