chemistry p12 discussion !!

[lychee26]

Can anyone tell me what was the ans of osmotic pressure one.ANd old lime new lime and no.40!

i did osmotic pressure decreases and structural formula. what about you?

 

[shressubha]

Can anyone tell me what was the ans of osmotic pressure one.ANd old lime new lime and no.40!

i did osmotic pressure decreases and structural formula. what about you?

chose option with increased pressure and structural isomer

 

[lychee26]

do you guys remember any more questions?

 

[Feroz]

For the osmotic pressure question, I chose: increase in osmotic pressure and structural isomers.

For the old lime to new lime question, new lime was CaCO3(s), so the equation was:
Ca(OH)2 + CO2 = CaCO3 + H2O

Question 40 was A, all of the listed compounds had the same C:H ratio:
aldehydes and ketones, carboxylic acids and esters, alkenes and ketones.

 

[lychee26]

For the osmotic pressure question, I chose: increase in osmotic pressure and structural isomers.

For the old lime to new lime question, new lime was CaCO3(s), so the equation was:
Ca(OH)2 + CO2 = CaCO3 + H2O

Question 40 was A, all of the listed compounds had the same C:H ratio:
aldehydes and ketones, carboxylic acids and esters, alkenes and ketones.

i did question 40 C.
what about the delta H ones?

 

[Feroz]

Q10, the hess law question, I said C, which was enthalpy of atomisation of carbon and hydrogen and enthalpy of formation of methane... I tried it too, it works, so Im guessing its the right answer.

 

[Mia4005]

i got the same!!
there was some question about the one which oxidises the reaction, i marked iodine..=/
i guess it is..anyone?

 

[lychee26]

i got the same!!
there was some question about the one which oxidises the reaction, i marked iodine..=/
i guess it is..anyone?

omg me too.

 

[Mia4005]

FINALLY!
some home

 

[lychee26]

hahaha.
Any more questions, do you rememberr?

 

[chemistrylover]

2. The following eqns the letters W X Y Z all represent wholo numbers. When correctly balanced, which equ requires one of the letters W X Y Z to be 5?
A. W c3H7COOH+ X O2---> Y CO2+ Z H2O
B W C4H8+ X O2---> Y CO2 + H2O
C W H3PO4+ X NaOH---> Y Na2HPO4+Z H2O
D. WNH3+XO2+ Z H2O


3. From which particle is the removal of an electron most difficult?
Cl- F- K+ Na+

39 Which compounds will produce CH3COOH when boiled under reflux with dilute OH- followed by acidification?
CH3CH2Cl
CH3COOCH3
CH3CN

for da 2nd qs,da 1st three cannot b da ans...man u did nt write da last equation properly.....i gave dat ans C.
nd da 3rd qs i think da ans is F- as it has da most ionisation energy....

 

[chemistrylover]

#mass of ammonia i found was 136kg,
#nd wat was da intermolecular forces present in Br2 nd CHCl3
#which substance has +2 oxidation state nd contains odd number of electrons
#osmotic pressure V=nRT
#lime mortar
#which substance was oxidised,i gave iodine
#there was a qs based on 70% yield,my ans came 1.54g
#how do u distinguish between alcohol and alkene
#Anode and Cathode for electrolysis of brine
#dere was a qs based on eutriphication
#

 

[chemistrylover]

guys i actually found 10 qs which were repeated....

 

[lychee26]

write down the answers as well.

 

[chemistrylover]

ammonia-136 kg
intermolecular forces-i gave induced forces for Br2 nd both induced forces and permanent forces for da oder 1
oxidation state +2 and odd no electrons-i agce NO
osmotic pressure-decrease and structural formula(i m nt sure)
lime mortar-da last option(i dnt remember da equation)
substance oxidised-iodine
yield-1.54 g
i dnt remember dat option-how can we differentiate alkene frm alcohol
anode-titanium and cathode steel
nd for eutriphication-first growth of algae,den oxygen gettin used up and den fishes dying

 

[Feroz]

ammonia-136 kg
intermolecular forces-i gave induced forces for Br2 nd both induced forces and permanent forces for da oder 1
oxidation state +2 and odd no electrons-i agce NO
osmotic pressure-decrease and structural formula(i m nt sure)
lime mortar-da last option(i dnt remember da equation)
substance oxidised-iodine
yield-1.54 g
i dnt remember dat option-how can we differentiate alkene frm alcohol
anode-titanium and cathode steel
nd for eutriphication-first growth of algae,den oxygen gettin used up and den fishes dying

Differentiate alkene from alcohol: Br2 in CCl4...
Your other answers seem right, just the osmotic pressure question, I doubt the osmotic pressure would have decreased. Oh well, i wrote increase and structural isomers.

 

[chemistrylover]

i dnt think we can use Br2 to differentiate,dis is cuz Br2 has to be in aqueous,bt Br2 was dissolved in CCl4 which is a non polar molecule,bt agen i m nt sure

 

[deepa1802]

For the osmotic pressure question, I chose: increase in osmotic pressure and structural isomers.

For the old lime to new lime question, new lime was CaCO3(s), so the equation was:
Ca(OH)2 + CO2 = CaCO3 + H2O

Question 40 was A, all of the listed compounds had the same C:H ratio:
aldehydes and ketones, carboxylic acids and esters, alkenes and ketones.

quick lime's formula is CaO and slacked lime is Ca(OH)2. z question asked about quick lime. So shouldn't the answer be CaO + CO2 = CaCO3.

 

[deepa1802]

i dnt think we can use Br2 to differentiate,dis is cuz Br2 has to be in aqueous,bt Br2 was dissolved in CCl4 which is a non polar molecule,bt agen i m nt sure

When Br2 is in aqueous state, you can get OH added to one carbon in the double bond and Br added to the other. But when you dissolve Br2 in an inert solvent, Br is added to both carbons

 

[lychee26]

what did you guys answer about delta H ? I did C. It was from the last ten questions.