Chemistry MCQ thread...

[libra94]

hope this helps!!

 

[sweetiepie]

@watscrackin answer is C
%yield = actual mass/calculated massx100
22/44x100
= 50%

i hope itx clear to u...

 

[Hateexams93]

wHy its C ??????isn't it suppose to be D ??????

 

[workinghard]

y do u think it ll b D ?!
i m seriously asking where r u making da 4th carbonyl group>?

 

[Hateexams93]

am i wrong ? if yes ,can u tell me what did i do wrong

 

[srukhan]

the ans is, C for both

 

[workinghard]

@srukhan 32 for 1st .. dat is HCO3- carbon's 6 e + oxygen's 3(8) + Hydrogen 1 + 1 extra electron since its an anion..
i ll do 2nd now
@hatexams i m stil tryin 2 fig it out maslf!! wait mayb i ll fig it out

 

[srukhan]

@srukhan 32 for 1st .. dat is HCO3- carbon's 6 e + oxygen's 3(8) + Hydrogen 1 + 1 extra electron since its an anion..
i ll do 2nd now[/quote
how do we know the anion is +1electron or +2electrons?

 

[workinghard]

r u sure its C n not B?! cux i get 38 % n i think its rite plx chk it! i m sonfused
cux its quite a general compound for one thing n i believe 2 mols of it r attached 2 cal cation n dat means itx power on da whole is -1 since Ca ia always Ca2+ ... geddit?!

 

[DeathDealer]

http://www.xtremepapers.me/CIE/Internat ... 6_qp_1.pdf
.
Can Any1 Help meh OUT ?
Ques 5 n Ques 34

 

[srukhan]

r u sure its C n not B?! cux i get 38 % n i think its rite plx chk it! i m sonfused
cux its quite a general compound for one thing n i believe 2 mols of it r attached 2 cal cation n dat means itx power on da whole is -1 since Ca ia always Ca2+ ... geddit?!

dude it's C anyhow no problem just post the method for it

 

[srukhan]

r u sure its C n not B?! cux i get 38 % n i think its rite plx chk it! i m sonfused
cux its quite a general compound for one thing n i believe 2 mols of it r attached 2 cal cation n dat means itx power on da whole is -1 since Ca ia always Ca2+ ... geddit?!

im still confused for Ca(HCO3)2 can elaborate some more, please?

 

[workinghard]

@srukhan wats confusing u ..? i cant help u generally ...
@deathdealer 4 34th MgCl2 conducts electricity wen molten by Mg2+ n Cl- ions
SiSl4 n PCl3 forms HCL n H3PO4 respectively wen added 2 water which can conduct electricity

4 5th hydrogen bonds exist only wen H is bonded 2 eithe of da 3 N O or F .... dese r highly electronegative....
n these r broken wen NH3 vapourixes ... geddit?!

 

[srukhan]

cool, it's ok i got the anion one.. could you please post the yield method?
and guys i got pink eye at the last moment, and damn it hurts do pray for all Insha'Allah it'll go well :^D

 

[workinghard]

kay ll pray n all
n normally u calc da mols of da reactant , find da molar ratio as in how many moles of reactant produce how many moles of products...den u multiply it wid Mr of da product... da ans ll b ur expected yeild
u divide da obtained yeild by da expected yeild n multiply it with 100 to get%
dats how u normally do it... can u tell me da yr n ques ppr so dat i can c how i solved it earlier.... n c wat s wrong... thnx!

 

[kingmanu]

 

[DeathDealer]

http://www.xtremepapers.me/CIE/Internat ... 6_qp_1.pdf
Ques 5 n 34 plzzzz !

 

[workinghard]

@kingmanu its D dat is one only cux oxidation state changes 4m +6 2 +4 of sulphur in sulfate 2 so2

 

[workinghard]

@deathdealer look above i already ansd da ques!

 

[kingmanu]