Chemistry: Post your doubts here!

[mittul8yu98]

how to deduce the rate determining step

 

[mittul8yu98]

do we need Kc and K partial pressure in A2 chemistry

 

[student3737]

Why doesn’t compound A react with Al2O3 or acidified K2Cr2O7? Shouldn’t it get oxidized ?

 

[student3737]

do we need Kc and K partial pressure in A2 chemistry

Generally yes, it’s useful to understand the concept of partial pressure , especially for paper 5, kc is extremely important for a levels , I see a lot of kc questions in the past papers,

 

[student3737]

How do you draw the repeating unit? I never seem to get these questions right, is there a certain method to use? How do you know what’s on the side chain?

 

[Ebrahim12]

how to deduce the rate determining step

I'm guessing you have the rate equation from previous parts?

The rate equation gives you the molecules involved in the rate determining step (or, if one of the reactants in the rate determining step is a product from another step and doesn't show up in the overall reaction equation, it will show the reactants that formed it) and the powers in the rate equation give the molar ratio in the rate determining step.
(this vid explains it better :

)

Why doesn’t compound A react with Al2O3 or acidified K2Cr2O7? Shouldn’t it get oxidized ?

Which paper is this?

How do you draw the repeating unit? I never seem to get these questions right, is there a certain method to use? How do you know what’s on the side chain?

Look at whats bonded to the two double bonded carbons, one has 2Hs, one has 1H and CO2H

 

[student3737]

I'm guessing you have the rate equation from previous parts?

The rate equation gives you the molecules involved in the rate determining step (or, if one of the reactants in the rate determining step is a product from another step and doesn't show up in the overall reaction equation, it will show the reactants that formed it) and the powers in the rate equation give the molar ratio in the rate determining step.
(this vid explains it better :

)


Which paper is this?

It’s summer 2013 variant 41

Look at whats bonded to the two double bonded carbons, one has 2Hs, one has 1H and CO2H

 

[Ebrahim12]

Why doesn’t compound A react with Al2O3 or acidified K2Cr2O7? Shouldn’t it get oxidized ?

Al2O3 is a reducing/dehydrating agent, so it wouldn't react.

We only have oxidation of alkyl benzene by KMnO4, so you have to say no reaction.

 

[student3737]

Al2O3 is a reducing/dehydrating agent, so it wouldn't react.

We only have oxidation of alkyl benzene by KMnO4, so you have to say no reaction.

So which groups do Cr2O7 oxidize ?

 

[blymphocytes]

Hy everyone,

Could anyone please upload the 2019 feb-march ppr 4? or atleast send me a link ...thank you!

 

[student3737]

Guys how do you solve this buffer solution question?

 

[mittul8yu98]

So which groups do Cr2O7 oxidize ?

kmno4 only oxidises only groups bonded to benzene

 

[mittul8yu98]

I'm guessing you have the rate equation from previous parts?

The rate equation gives you the molecules involved in the rate determining step (or, if one of the reactants in the rate determining step is a product from another step and doesn't show up in the overall reaction equation, it will show the reactants that formed it) and the powers in the rate equation give the molar ratio in the rate determining step.
(this vid explains it better :

)


Which paper is this?



Look at whats bonded to the two double bonded carbons, one has 2Hs, one has 1H and CO2H

thanks man

 

[mittul8yu98]

sw

Guys how do you solve this buffer solution question?

which year

 

[student3737]

sw


which year

2013 summer

 

[student3737]

I'm guessing you have the rate equation from previous parts?

The rate equation gives you the molecules involved in the rate determining step (or, if one of the reactants in the rate determining step is a product from another step and doesn't show up in the overall reaction equation, it will show the reactants that formed it) and the powers in the rate equation give the molar ratio in the rate determining step.
(this vid explains it better :

)


Which paper is this?



Look at whats bonded to the two double bonded carbons, one has 2Hs, one has 1H and CO2H

But what about this structure ? I got CH2-CH-COOH as the monomer but the marking scheme says CH2=CH-COOH, why is there a double bond?

 

[blymphocytes]

Hy everyone,

Could anyone please upload the 2019 feb-march ppr 4? or atleast send me a link ...Pleasee

 

[mittul8yu98]

does lialh4 reduce carboxylic acids

 

[blymphocytes]

does lialh4 reduce carboxylic acids

Yes, they are reduced to primary alcohols

 

[student3737]

For b iv) how do we know how to form the equation ? Why is it NaSnO3?