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37:Can you help me with Q1 D,
22D,
30A,
33D,
37B of this paper
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w13_qp_13.pdf
11qp12
i am working on it Metanoia
THNKS N nice explanation11qp12
short answer, cross the Al3+ and C4- charges, though it might not always work.
Long answer
Understand that whatever moles of C we have at the beginning will eventually be the same number of moles of C in CO2 at the end.
Let x and y be the ratio of Al and C respectively.
AlxCy --->???---> CO2
Working backwards from CO2,
moles of CO2 = 72/24 000 = 0.003 moles = moles of C in AlxCy
Going through the options
A Al 2C3, moles of Al2C3 = 0.144/90 = 0.0016, moles of C = 0.0016 x 3 = 0.0048 (incorrect)
B Al 3C4 , moles of Al3C4 = 0.144/129 = 0.0016, moles of C = 0.0016 x 4 = 0.0045 (incorrect)
C Al 4C3 , moles of Al4C3 = 0.144/144 = 0.001, moles of C = 0.001 x 3 = 0.003 (BINGO!)
D Al 5C3
dumb me thanks againquestion33:
the questions says that methanoic acid IS stronger acid because it has a LOWER pH. it means that obviously it disassociates more. and if the rest two were true then it would have been weaker acid. tha
Thanks and forw13qp13
Q1.
N in NH4+ is -3, increases by 4 units to from +1 in N2O
N in NO3- is +5, decreases by 4 units to from +1 in N2O
Q22.
A. Is not good as we might get multi substitutions
B. Is not good as we get dichloropropane
C. Cl- will not replace OH
D. Cl will replace at the OH position
Q30.
A. CH2-CH2-CCl2-CCl2-CH2-
Coloured are the repeating units that come from the monomers
Q33. Lower pH means higher conc of H+, due to more H+ released. Which statements are you confused about?
Q37. Which statement are you unsure of?
Statement 3: No COOH group to react with sodium carbonate
lol happens with me so many times but i don't erase it might help the person understand morei am working on it Metanoia
i had to erase some answer because you had already answered them. please tell me which one you are doing so i do other queries instead.
Aldehyde is present which get oxidised to -COOHdumb me thanks again
Thanks and for
Q37 the first one how can it be oxidized when no alcohol is present
Won't it be x2= 4 (1-x)^2 -> x= 2(1-x) -> x= 2-2x -> 3x=2 -> x=2/3?
calcium has 2+ charge so there must be two CO2H
yes i made a mistake. it had to be x²Won't it be x2= 4 (1-x)^2 -> x= 2(1-x) -> x= 2-2x -> 3x=2 -> x=2/3?
aldehyde will be oxidised to CO2Hdumb me thanks again
Thanks and for
Q37 the first one how can it be oxidized when no alcohol is present
Yes, two with methanoic acid, one with ethanoic and one with propanoic. So total are 4.but the answer to question 23 is c tht is 4 esters
wah... thanksWon't it be x2= 4 (1-x)^2 -> x= 2(1-x) -> x= 2-2x -> 3x=2 -> x=2/3?
question 23:
i am working on it Metanoia
i had to erase some answer because you had already answered them. please tell me which one you are doing so i do other queries instead.
Maybe we can quote and "click reply" immediately.
And then take your time to add the answers by editing the posts.
If it turns out we are repeating answers even after that, just leave them posted. Sometimes, it might be good to have differing approaches to the same questions.
you can take rest. i will handle these childish questionsMaybe we can quote and "click reply" immediately.
And then take your time to add the answers by editing the posts.
If it turns out we are repeating answers even after that, just leave them posted. Sometimes, it might be good to have differing approaches to the same questions.
Quite a few questions are repeated, so I just copied and paste what I type just a day or two ago.
Anyway, I will be here for just only a while longer .
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