Chemistry: Post your doubts here!

[donor]

http://www.chemguide.co.uk/organicprops/alkenes/kmno4.html​

​

pls some one tell me at the end of this page there is a question in this summary ....... related to this:​

saudha said: ↑​

​

how do u get a ketone and a carbon dioxide in addition to 2 methyl propane...with hot concentrated KMNO4​

​

Amy farvin said: ↑​

​

i too dont get it,to explain u.. if anyone knowz plz help us... ​

A CH2 with a double bond always give carbon dioxide and water.
If there are two alkyl groups attached to the double boded carbon atom it will give a Ketone
so 2 methyl propene will give propanone, carbondioxide and water as product with hot conc. KMnO4

 

[Gémeaux]

For the practical paper, if our titre volumes are each with a difference of 0.1 with the previous, which one to include for our average volume. lyk if we have 20.4, 20.2 and 20.3 cm^3?

 

[Oliveme]

For the practical paper, if our titre volumes are each with a difference of 0.1 with the previous, which one to include for our average volume. lyk if we have 20.4, 20.2 and 20.3 cm^3?

Take any combination eg. 20.4 and 20.3 or 20.3 and 20.2. But the best way is to add all three and divide by 3.

 

[Saad (سعد)]

Take any combination eg. 20.4 and 20.3 or 20.3 and 20.2. But the best way is to add all three and divide by 3.

No! Don't do that.

Take the last two volumes. The first one is a rough titre and is not to be used.

 

[Chooi1993]

Anyone know how to do 6 (e)?
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s04_qp_4.pdf
4(b(ii)?http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w08_qp_4.pdf
Please reply me as soon as possible tomorrow is my exam Thanks

 

[Goku]

Can someone please explain to me the shifting of the equilibrium to left or right? :/
I am so confused about it.
Do we mean the page wala left or right or the actual left or right
and is the product side wala arrow shifting to the right
Someone pleeeeeeease help!!! :'(

 

[oldfashionedgirl]

xcuse me oldfashionedgirl cud u change your profile pic please . tnx . it is very disturbing .

its an epic,classic old movie and a block-buster hit -______-
ur the first person that i've heard call ANYTHING related to this movie 'disturbing'

 

[Goku]

its an epic,classic old movie and a block-buster hit -______-
ur the first person that i've heard call ANYTHING related to this movie 'disturbing'

BESTEST.MOVIE.EVER.

 

[CaptainDanger]

^ Don't discuss that here in this thread... You can discuss about it on the profile posts...

 

[shamil]

Reaction kinetics:
are these the only equations:?

Rate= k x conc.

rate = change in conc./ change in time

????? or is there anything im missing cuz it feels like it when i answer the papers and the MS don't really help me out much with this either. Thank you

 

[shamil]

Does anyone have a summary of everything we need to know for analytical chem? IF so please do post, thank you

 

[Chooi1993]

Anyone know how to do 6 (e)?
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s04_qp_4.pdf
4(b(ii)?http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_w08_qp_4.pdf
Please reply me as soon as possible tomorrow is my exam Thanks

 

[vita199]

an sum1 plzzz help in these questionss....i dont get how electrode potentials increases or decreases when u increase conc of of the reactants..these are the papers.q3 of oct/2010/41 and q5c of oct/2010/43

 

[draddin]

an sum1 plzzz help in these questionss....i dont get how electrode potentials increases or decreases when u increase conc of of the reactants..these are the papers.q3 of oct/2010/41 and q5c of oct/2010/43

Don't worry. This type of question will never come out again. Trust me.

 

[Casablanca]

its an epic,classic old movie and a block-buster hit -______-
ur the first person that i've heard call ANYTHING related to this movie 'disturbing'

Hah, I'm a guy, and even I liked that movie.

 

[angelicsuccubus]

http://www.chemguide.co.uk/organicprops/alkenes/kmno4.html​

​

pls some one tell me at the end of this page there is a question in this summary ....... related to this:​

saudha said: ↑​

how do u get a ketone and a carbon dioxide in addition to 2 methyl propane...with hot concentrated KMNO4​

​

Amy farvin said: ↑​

i too dont get it,to explain u.. if anyone knowz plz help us... ​

I didnt check the link but basically if an alkene has two hydrogens on one end and two alkyl groups on the other, when hot conc KMnO4 is added, the double bond breaks, the side with the two alkyl groups turns into a ketone .. and the side with the two hydrogen groups gets oxidised into CO2 and H2O

 

[MysteRyGiRl]

Can someone please explain to me the shifting of the equilibrium to left or right? :/
I am so confused about it.
Do we mean the page wala left or right or the actual left or right
and is the product side wala arrow shifting to the right
Someone pleeeeeeease help!!! :'(

eeee da products are on ur ryt syd in an equation
eg: 2Na+ Cl2 ---> 2NaCl
NaCl is da product formed here and Na and Cl are da reactants. for pressure, count da number of moles 2 know where da equilibrium shifts.here Na is 2 and 1 of Cl so total number of moles here are 3.and da products moles are just 2 so if pressure increases, equilibrium shifts 2 NaCl ie right syd cz there r less nmbr of moles there.
for concentration,if conc of NaCl is increased, equ. wil shift 2 da left syd ie Na + Cl (reactants) syd.lykwise if conc of NaCl is decreased or Na (or Cl) increased,equ will shift 2 da ryt syd 2 minimise da effect
for temperature its easier to learn just 1 variable lyk if rctn is exo,increacing temperature shifts equ. 2 da reactnats syd... if its endo, increasing temp shifts equ 2 da products syd and vice versa for decreasing temp

hope u understandif dont always welcum 2 ask again

 

[angelicsuccubus]

http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s07_qp_4.pdf

What are they talkin about in d(i)?

 

[Utsav.]

can ny1 tell me what are the important aspects or topics should i cover for the Bio-chemistry?
nd plz dont say me the syllabus just some of the most frequently asked sections!! pls

 

[Goku]

eeee da products are on ur ryt syd in an equation
eg: 2Na+ Cl2 ---> 2NaCl
NaCl is da product formed here and Na and Cl are da reactants. for pressure, count da number of moles 2 know where da equilibrium shifts.here Na is 2 and 1 of Cl so total number of moles here are 3.and da products moles are just 2 so if pressure increases, equilibrium shifts 2 NaCl ie right syd cz there r less nmbr of moles there.
same goes for concentration,if conc of NaCl is increased equ. wil shift 2 da left syd ie Na + Cl (reactants) syd.
for temperature its easier to learn just 1 variable lyk if rctn is exo,increacing temperature shifts equ. 2 da reactnats syd... if its endo, increasing temp shifts equ 2 da products syd and vice versa for decreasing temp

hope u understandif dont always welcum 2 ask again

Omg thankyoooou!!
that helped a lot!! :')

for temperature its easier to learn just 1 variable lyk if rctn is exo,increacing temperature shifts equ. 2 da reactnats syd... if its endo, increasing temp shifts equ 2 da products syd and vice versa for decreasing temp
^^ could you please tell me why though? isnt exothermic bond formaton? so then why does it shft to the reactants side :/