Chemistry: Post your doubts here!

[princess Anu]

but I remember exactly it said write the displayed formula of 2 structural isomers of pentane 3 one :/

 

[ashcull14]

This question actually came in my paper..
the first one was already drawn and we had to make two others.
I made the second one ,you have drawn, but i am doubtful because this changes the position of functional group from 1 to 2.. what should be the answer

wat do you mean by 1 to 2??....Que is about structural isomer of a ketone whose name is pentane 3 one ryt......in structural isomer u can alter the position of functional group except for carbon 1 and carbon 4......I have place the CO group on Carbon 2 not 1 or 4 which means that it is correct

 

[My Name]

That is the ester right?

Then the question states that Q is hydrolyzed with sulfuric acid

C4H8O2 --> acid + alcohol

Then the mixture was oxidized to obtained a single product, R, in other words, the alcohol in the above reaction is oxidized to become the same compound as the acid.

It simply means the alcohol has the same number of carbons as the acid.

We have 4 carbons to divide equally among the two....so the alcohol was ethanol and the acid was ethanoic acid.

When this mixture was oxidized, all we end up with is a sample of ethanoic acid.

So its like the Ester has 4 carbon atoms and we distribute them equally so 2 which is ETH ?
I think I get it.
Thank you

 

[Metanoia]

You mean this does happen?

If we write it as NaCl + H2O --> NaOH + HCl

The forward reaction really really really small compared to the backward reaction. The equilibrium lies very much to the left.

Does the forward reaction happen? Not to any extent to make it significant.

 

[princess Anu]

wat do you mean by 1 to 2??....Que is about structural isomer of a ketone whose name is pentane 3 one ryt......in structural isomer u can alter the position of functional group except for carbon 1 and carbon 4......I have place the CO group on Carbon 2 not 1 or 4 which means that it is correct

this would have happened if they said pentanone. but here they have specified the position of Functional group.

 

[ashcull14]

one more could be if u place the CO group on second carbon atom rather than 3rd

My concern is that these are actually "isomers of pentanone", not "isomers of penton-3-one".

There is only one structure that penton-3-one, CH3CH2COCH2CH3.

So the question wording is a bit strange.[/QUOTE]
pentane 3 one is just a name to coinfuse I guess actually pentan3one is pentanone just func group on carbon 3

 

[Metanoia]

So its like the Ester has 4 carbon atoms and we distribute them equally so 2 which is ETH ?

Exactly. So we get ethanol and ethanoic acid. And the ethanol later gets oxidized to ethanoic acid. Giving us a single product in the end.

 

[My Name]

Exactly. So we get ethanol and ethanoic acid. And the ethanol later gets oxidized to ethanoic acid. Giving us a single product in the end.

I understood
Alhamdulillah!

 

[The Chill Master]

That is the ester right?

Then the question states that Q is hydrolyzed with sulfuric acid

C4H8O2 --> acid + alcohol

Then the mixture was oxidized to obtained a single product, R, in other words, the alcohol in the above reaction is oxidized to become the same compound as the acid.

It simply means the alcohol has the same number of carbons as the acid.

We have 4 carbons to divide equally among the two....so the alcohol was ethanol and the acid was ethanoic acid.

When this mixture was oxidized, all we end up with is a sample of ethanoic acid.

And ya should in every case when we have a similar type of question should we divide equally like what will we do if we have 5 carbon atoms?

 

[My Name]

And ya should in every case when we have a similar type of question should we divide equally like what will we do if we have 5 carbon atoms?

good question
by that you mean like when they say SINGLE product?

 

[The Chill Master]

good question
by that you mean like when they say SINGLE product?

Ya

 

[Metanoia]

And ya should in every case when we have a similar type of question should we divide equally like what will we do if we have 5 carbon atoms?

In this case, we divide equally because the question gives us the information that "a single product was obtained after oxidizing."

We don't assume that we divide equally for all other questions unless the clues tells us so.

As for your example of 5 carbons, there is no way to obtain a single product after oxidizing.

 

[sid2333]

Can anybody help me out with this question?


25 Use of the Data Booklet is relevant to this question.
2.30 g of ethanol were mixed with aqueous acidified potassium dichromate(VI) and the desired
organic product was collected by immediate distillation under gentle warming. The yield of
product was 70.0 %.
What mass of product was collected?
A 1.54 g B 1.61 g C 2.10 g D 2.20 g

 

[sid2333]

26 Which pair of reactions could have the same common intermediate?
W CH3CH2CH3 → intermediate → (CH3)2CHCN
X CH3CH(OH)CH3 → intermediate → (CH3)2C(OH)CN
Y CH3CH=CH2 → intermediate → CH3CH(OH)CH3
Z CH3CO2CH2CH2CH3 → intermediate → CH3CH2CH2Br
A W and X B W and Y C X and Z D Y and Z

 

[sid2333]

14 Use of the Data Booklet is relevant to this question.
When 3.00 g of an anhydrous nitrate of a Group II metal is decomposed, 1.53 g of gas is
produced.
What is the nitrate compound?
A beryllium nitrate
B calcium nitrate
C magnesium nitrate
D strontium nitrate

 

[sid2333]

10 The enthalpy change of the neutralisation given below is –114 kJ mol–1.
2NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2H2O(l)
By using this information, what is the most likely value for the enthalpy change of the following
neutralisation?
Ba(OH)2(aq) + 2HCl(aq) → BaCl2(aq) + 2H2O(l)
A –57 kJ mol–1 B –76 kJ mol–1 C –114 kJ mol–1 D –228 kJ mol–1

 

[Xaptor16]

can someone please help me with question 4?i know the equation is PV=nRT i just have problem finding the volume and the number of moles
the answer is A btw

 

[My Name]

 

[My Name]

correct answer is D

 

[My Name]

Answer is C