ANY DOUBTS HERE!!!

[sweetie]

more chemistry doubts..

cud u plz help me in  Q.30> the ms says 'A' but why is it not ethanol?
                            Q.20> ms says "c"
                            Q.2>   ms says ' B'


ruby, is it chemistry?

[nid404]

I'm a lil worked up atm....please give me a day
Thanks

[ruby92]

more chemistry doubts..

cud u plz help me in  Q.30> the ms says 'A' but why is it not ethanol?
                            Q.20> ms says "c"
                            Q.2>   ms says ' B'


ruby, is it chemistry?

ohh sorryy yeh

[sweetie]

C₆H₁₂ + 9O₂ ----> 6CO₂ + 6H₂O

so, in 'P' 6*18 = 108g of water r absorbed which = increase in mass at P

at Q 6*44=264g of CO₂ r absorbed = increase in mass at Q

so 108/ 264= 0.41 = Mp/ Mq

hope u understud

[ruby92]

Thank You
paper 2 O/N 2003 Q3...
all the parts with the calculations involved 

[nid404]

be a lil more specific
or do u want the whole q to be done?

[ruby92]

b ii,iii
cii and d

[nid404]

b)ii)H=mcdt
=200x4.2X12.2=10.25KJ

iii) 1g gives out 10.25 KJ
    1 mole=??
1 mole of calcium=40.1g
so H released with 40.1g=40.1X10.25=- 411KJ/mol  exothermix(heat released)

c)ii) Ca(s) + 2H2O(l) ? Ca(OH)2(aq) + H2(g) ?H = –411
dh of formation of water= -286kJ/mol  since 2 moles of water =2X-286= -  572
dh reaction= h of products-h of reactants
      -411  = X- (-572)
       X= -411-572=-983KJ/mol

d) In b(ii) 1g of Ca ws used...1g of ca= 1/40.1 moles=0.025moles
   Ratio of Ca:H2=1:1
therefore 0.025 moles of H2 formed
1 moles occupies 24dm3
0.025mol=0.025X24=0.6dm3/ 600cm3

[sweetie]

more chemistry doubts..

cud u plz help me in  Q.30> the ms says 'A' but why is it not ethanol?
                            Q.20> ms says "c"
                            Q.2>   ms says ' B'

plzzzzzzzz, sum1 answer my que's

[nid404]

Please be patient....y r u getting furious..
We all have to study here....some1 will always answer when free

2) 30% x= 144
x=144X100/30=480g

P2=32X2=64g
% of P2= 64/480 X100
=13.1%

20) U have to try out all the possible outcomes with 4 carbons
You get 5 possibilities....try it

30) Ethanol will not react with NaOH at all....
Ethanol will only react with metals, not metal compounds..keep that in mind

[sweetie]

newayz, am sorry

for Q20. i got da 3 structural isomers( primary, secondary & tertiary)
            one cis and trans.
            1 optical isomers and its reflection

and this adds up to  7

OR do we consider both the cis and trans as 1 isomer?

[ruby92]

cis trans and optic isomers are not possible since it has a single bond.
stereo isomerism is only possible for compounds with a double bond
they can have 5 structural only, ie primary alcohol and secondary alcohol and tertiary alcohol, two of the methyl groups can also be shifted.
ans is therefore C) 5

[sweetie]

 oops , i just missed dat 

 but optical isomers dont have
double bonds ,

so ya 3 structural and 2 optical,  which adds up to 5..... rite??

Thank You

[ruby92]

ohh sorry yeh optical isomers dont have double bonds....
i think ur pretty much rite

[sweetie]

Thank You

Q.19. i never get such que's rite, any hint...
Q20. i found 6 but the ms says 8.. how???
Q28. isnt it dat 1molecule of 2,4 DNPH is needed for each ketone grp ( By the way what's  X )??


thanks 4 any help