Chemistry confusions !

[AStarHunter]

Ok, so i was doing this past paper qs and then it says:

Describe a chemical test that would distinguish between zinc carbonate and zinc oxide....

Since this is an old paper, the mark scheme isn`t the original one and it isn`t very reliable. So, how would u guyz attempt it ?!
I would say add dilute hydrochloric acid and the gas given off by zinc oxide would relight a glowing splint and the gas given off by zinc carbonate will turn the limewater milky. So, is this right ?!

Oh, and guyz, does copper oxide dissolve in water or not ? I think it dissolves in acid when heated, is that correct ? And what about zinc oxide, does it dissolve in water and acid ? And does it react with them ?!

Confused...

 

[xIshtar]

Ok, so i was doing this past paper qs and then it says:

Describe a chemical test that would distinguish between zinc carbonate and zinc oxide....

Since this is an old paper, the mark scheme isn`t the original one and it isn`t very reliable. So, how would u guyz attempt it ?!
I would say add dilute hydrochloric acid and the gas given off by zinc oxide would relight a glowing splint and the gas given off by zinc carbonate will turn the limewater milky. So, is this right ?!

Oh, and guyz, does copper oxide dissolve in water or not ? I think it dissolves in acid when heated, is that correct ? And what about zinc oxide, does it dissolve in water and acid ? And does it react with them ?!

Confused...

Neither dissolve in water or acid.. They react with acid. Your first test is right for distinguishment, as Water is produced in the ZnO reaction.

 

[gary221]

Ok, so i was doing this past paper qs and then it says:

Describe a chemical test that would distinguish between zinc carbonate and zinc oxide....

Since this is an old paper, the mark scheme isn`t the original one and it isn`t very reliable. So, how would u guyz attempt it ?!
I would say add dilute hydrochloric acid and the gas given off by zinc oxide would relight a glowing splint and the gas given off by zinc carbonate will turn the limewater milky. So, is this right ?!

Oh, and guyz, does copper oxide dissolve in water or not ? I think it dissolves in acid when heated, is that correct ? And what about zinc oxide, does it dissolve in water and acid ? And does it react with them ?!

Confused...

abt d first one ur correct
add an acid and test gas given off wth limewater if turns milky so its carbonate
abt CuO im not sure,but since its a base it will react wth acid
same 4 ZnO

 

[gary221]

hey guys cud sum1 explain this???



the ans is C, but why???

 

[Keeemoman]

Ok, so i was doing this past paper qs and then it says:

Describe a chemical test that would distinguish between zinc carbonate and zinc oxide....

Since this is an old paper, the mark scheme isn`t the original one and it isn`t very reliable. So, how would u guyz attempt it ?!
I would say add dilute hydrochloric acid and the gas given off by zinc oxide would relight a glowing splint and the gas given off by zinc carbonate will turn the limewater milky. So, is this right ?!

Oh, and guyz, does copper oxide dissolve in water or not ? I think it dissolves in acid when heated, is that correct ? And what about zinc oxide, does it dissolve in water and acid ? And does it react with them ?!

Confused...

Man for the test of zinc oxide its incorrect cause it will form water as it neutralises HCL
But zinc carbonate is correct for sure
CuO I am not sure but u can dissolve in water cause its an ionic compound
The same for zinc oxide
but in both case I think u need to pass steam not water in liquid state as well as u need to heat it.

 

[Keeemoman]

hey guys cud sum1 explain this???



the ans is C, but why???

because the second OH group is carboxylic acid group so it will react with sodium hydroxide in order to neutraise it.
But for ethanol would be impossible as it could be neutral or alkaline

 

[gary221]

hey guys cud sum1 explain this???



the ans is C, but why???

because the second OH group is carboxylic acid group so it will react with sodium hydroxide in order to neutraise it.
But for ethanol would be impossible as it could be neutral or alkaline

oh got it!
thnx!!

 

[CaptainDanger]

Yes the test for ZINC OXIDE is incorrect.... Check the answer in examiner report... It may help....

 

[Wearewhoweare]

Guys i'm not sure which one is correct..

 

[xIshtar]

The 2nd one.. You need to show the other bonds, brackets, and the n outside, to show that it is a repeat unit.

 

[AStarHunter]

Guys i'm not sure which one is correct..

I would do 2 but you have to show continuation of the bonds cause they give a mark for that.

 

[Wearewhoweare]

Yea i know that i just didn't have space to draw it lol but thanks

 

[SmartNour]

hey guys cud sum1 explain this???



the ans is C, but why???

Cuz the 2nd OH represent the carboxylic acid group which is acidic so it will react with NaOH