Chemistry: Post your doubts here!

[Bishnu Dev]

View attachment 62716
CAN ANYONE EXPLAIN HOW TO GET X AND Y?

First find out the volume of CO2 which is formed by the combustion....
volume of CO2 = 170-110 = 60 cm3

X = volume of CO2 / Volume of Alcohol
X = 60 / 20 = 3

Now find volume of water
Volume of Water = 250 - 170 = 80 cm3
Y / 2 = Volume of H2O / Volume of Alcohol
Y / 2 = 80 / 20 = 4
So Y = 8

 

[i_try9621]

Anyone please help me with V and W ? Shouldn't Oxygen be replace with O-H bond ?

 

[i_try9621]

Someone help me with this please? I have a problem with understanding what test 1 and test 5 is for . Also which test is for Amine and Amide here?

 

[Thought blocker]

Anyone please help me with V and W ? Shouldn't Oxygen be replace with O-H bond ? View attachment 62717 View attachment 62718

but y?

 

[i_try9621]

but y?

I mean from C=O bond to C-OH bond or Am I wrong?

 

[i_try9621]

but y?

I think I found my mistake in there . Just to clarify, this is reduction of Amide to Amine yes?

 

[i_try9621]

Anyone help me with the questions please?

 

[Daniel Jeng]

Anyone please help me with V and W ? Shouldn't Oxygen be replace with O-H bond ? View attachment 62717 View attachment 62718

In this question test 1 is for the basic identification of whether the substance is an amide or amine. Since M does not react with the acid, this means that the substance must contain an amide group (it is neutral). Since the only other group we know containing nitrogen is amine, and it would react with the acid, we can safely assume the other substances all contain an amine group. In terms of test 5, it can test for either a hydroxy group, an acid, nucleophilic substitution or hydrolysis. remember that either an acid or an alkali can be used in hydrolysis. For the reaction with M, you should be able to see that the amide has hydrolysed into phenylamine and sodium propanoate.

EDIT: My bad, this is for the second question

 

[RJ72NL]

Anyone doing Chemistry Practical 34 on the 17th October??? Pls help if possible✌

 

[Bishnu Dev]

Anyone doing Chemistry Practical 34 on the 17th October??? Pls help if possible✌

It's on 25th October... It's Paper 2 tomorrow

 

[Bishnu Dev]

I am also waiting for any help possible on Paper 34

 

[RJ72NL]

Yes, sorry...my bad.... Anyone?

 

[i_try9621]

In this question test 1 is for the basic identification of whether the substance is an amide or amine. Since M does not react with the acid, this means that the substance must contain an amide group (it is neutral). Since the only other group we know containing nitrogen is amine, and it would react with the acid, we can safely assume the other substances all contain an amine group. In terms of test 5, it can test for either a hydroxy group, an acid, nucleophilic substitution or hydrolysis. remember that either an acid or an alkali can be used in hydrolysis. For the reaction with M, you should be able to see that the amide has hydrolysed into phenylamine and sodium propanoate.

EDIT: My bad, this is for the second question

Thanks for that

 

[Bishnu Dev]

Why is the percentage uncertainty in 1 C (ii) is 3?
I got 1%

 

[Bishnu Dev]

Alright, Bishnu, typing my response to you.

bro please help.... i have posted the question above this post..........

 

[i_try9621]

bro please help.... i have posted the question above this post..........

(0.5-0)/50 = 0.01 x 100 = 1%
We used the measuring cylinder to transfer 150cm^3 of Hydrogen Peroxide so each time there is an uncertainty of 1% . In this case , it's 3 times so it's 3%

 

[i_try9621]

bro please help.... i have posted the question above this post..........

Is your P3 exam tomorrow?

 

[Bishnu Dev]

yes

 

[Bishnu Dev]

so what were the ions? chemistry practical 34

 

[i_try9621]

From 52/M/J/16 . Anyone please explain 1) a)?