Chemistry Test of Ions

[wooowooowoo]

Q6)b) http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_62.pdf
plz help

You have to carry out titration in this reaction
So first take the acid in the burette

• Fill the nitric acid in the burette
• Add the Kleen up in a flask
• Add phenolphthalein (indicator to check how much acid used up)
• Add the nitric acid drop by drop in the flask until the color changes from pink to colorless
• Note volume of the acid used.
• Now use the mole formula to get the concentration (details are not usually required I guess)

 

[wooowooowoo]

lol cake thing it depends on hw hungry i am but yea got it thanks.. ummmm i don rem the year it was like potassium chloride was being made and the reactants were hcl & koh ,,, hcl was 19cm3 & koh was 25cm3 i guess ,n the ques was which is more concentrated? sooo yea which one?

I don't quite understand. Sorry

 

[thats_me]

I don't quite understand. Sorry

oh no problem ill ask wen i cum across the ques again ,,nyways thanks for ur help

 

[ZainH]

Err, the test for ions and stuff you posted by cambridge on the first page doesn't include the results when things are heated..
Any idea where I could find results of when compounds or salts are heated. Like color results, etc.

 

[wooowooowoo]

Err, the test for ions and stuff you posted by cambridge on the first page doesn't include the results when things are heated..
Any idea where I could find results of when compounds or salts are heated. Like color results, etc.

Download the attached file

 

[ZainH]

Download the attached file

Ah k, but still I can't even solve the question WITH ALL THOSE TESTS.
Im screwed.. the question is 4) http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s03_qp_6.pdf

 

[wooowooowoo]

Ah k, but still I can't even solve the question WITH ALL THOSE TESTS.
Im screwed.. the question is 4) http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s03_qp_6.pdf

Do the recent questions, they're simpler for the test of ions.

Gas tested with limewater
Only Co2 is tested with limewater
Result : Fizzz (bubbles/efferevescense) and limewater turns milky

To the first portion was added
excess aqueous sodium
hydroxide, a little at a time. pale blue precipitate
(ii) To the second portion was
added excess aqueous
ammonia, a little at a time.

It's blue PPT with NaOH which means it's copper
So excess NH3 will give Blue PPT which will dissolve in excess to give deep blue solution

The filtrate from (b) was divided
into three approximately equal
portions.
(i) To the first portion were added
drops of aqueous sodium
hydroxide, a little at a time with
shaking.

As it said in the question, it's a zinc salt

NaOH will give White ppt soluble in excess
Sam with NH3 - White PPT soluble in excess

To the third portion were added
drops of dilute hydrochloric acid
and aqueous barium chloride. white precipitate

This is a test for the presence of sulphate. It gave a white ppt (positive result)

So D is a zinc sulphate which is hydrated as condensation formed in the first reaction

E is copper (Cu2+)

 

[ZainH]

Do the recent questions, they're simpler for the test of ions.

Gas tested with limewater
Only Co2 is tested with limewater
Result : Fizzz (bubbles/efferevescense) and limewater turns milky



It's blue PPT with NaOH which means it's copper
So excess NH3 will give Blue PPT which will dissolve in excess to give deep blue solution


As it said in the question, it's a zinc salt

NaOH will give White ppt soluble in excess
Sam with NH3 - White PPT soluble in excess



This is a test for the presence of sulphate. It gave a white ppt (positive result)

So D is a zinc sulphate which is hydrated as condensation formed in the first reaction

E is copper (Cu2+)

THANKS A TON! I'll solve the more recent test for ion questions, but thanks. This helped x)

 

[Sara5396]

I'M NOT ABLE TO STUDY TEST FOR IONS.... SOMEONE HELPP

 

[wooowooowoo]

I'M NOT ABLE TO STUDY TEST FOR IONS.... SOMEONE HELPP

You have to mug that all up.
Read each test at least 5 times.
Try writing them, you tend to remember better when you write

 

[ThatReallyReallyWeirdDude]

lol cake thing it depends on hw hungry i am but yea got it thanks.. ummmm i don rem the year it was like potassium chloride was being made and the reactants were hcl & koh ,,, hcl was 19cm3 & koh was 25cm3 i guess ,n the ques was which is more concentrated? sooo yea which one?

HCl
The reaction is:
HCl + KOH -> KCl + H20
So one mole of KOH is needed for each mole of HCL
So that means the number of moles of KOH in 25cm3 KOH is the same as the number of moles of HCl in 19cm3 of HCl
The HCl is more concentrated because it has the SAME number of moles in a smaller volume. Concentration = No. of Moles divided by volume, so the lower the volume the higher concentration. Alternatively you could think of it as the same number of moles packed in a smaller space (volume)

 

[wooowooowoo]

THANKS A TON! I'll solve the more recent test for ion questions, but thanks. This helped x)

You're welcome

 

[ThatReallyReallyWeirdDude]

Q6)b) http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_62.pdf
plz help

Ahaha
Ironic
We had this question in our mocks recently
It's simple:
Pour 25cm3 of kleenup into a beaker.
Fill a burette with nitric acid of known concentration.
Add an phenopthalein to the kleenup
Titrate the nitric acid against the kleenup until it reaches the end point (i.e. until the mixture of kleenup and nitric acid is neutral i.e. all ammonia in kleenup has reacted)
Note the volume of nitric acid.
According to equation:
HNO3 + NH3 -> NH4NO3
One mole of nitric acid reacts with one mole of Ammonia. You can use concentration/volume of Nitric Acid used to find the no. of moles of HNO3, and this is the no. of moles of Ammonia. We also have the volume of ammonia (25cm3) and concentration= no. of moles divided by volume, so using that you can find concentration.A bit long, I know. I don't think you need all the details about calculations,

 

[ZainH]

http://www.xtremepapers.com/papers/CIE/Cambridge%20IGCSE/Chemistry%20(0620)/0620_s04_qp_6.pdf

Q4)b)ii)

 

[thats_me]

I'M NOT ABLE TO STUDY TEST FOR IONS.... SOMEONE HELPP

well try doin this make a chart i guess il help
Add aq sodium hydroxide if ppt doesnot form its ammonia
if it does ,, thn is it coloured ?if yes then 3 possibilities pale blue: Cu2+,, dirty green :Fe2+ ,, rusty brown :Fe3+
all of these in soluble in excess
if not coloured i.e white then 4 possibilities Ca2+,, Zn2+ ,, Pb2+ ,, Al3+
Ca2+ gives a white ppt (insoluble) but the rest being transition metals disolve giving colourless sol

 

[Sara5396]

I shall try that... thank you

 

[ThatReallyReallyWeirdDude]

Do the recent questions, they're simpler for the test of ions.

Gas tested with limewater
Only Co2 is tested with limewater
Result : Fizzz (bubbles/efferevescense) and limewater turns milky



It's blue PPT with NaOH which means it's copper
So excess NH3 will give Blue PPT which will dissolve in excess to give deep blue solution


As it said in the question, it's a zinc salt

NaOH will give White ppt soluble in excess
Sam with NH3 - White PPT soluble in excess



This is a test for the presence of sulphate. It gave a white ppt (positive result)

So D is a zinc sulphate which is hydrated as condensation formed in the first reaction

E is copper (Cu2+)

Hmmm
Are you supposed to say it's ZINC SULPHATE or that the compound contains Zinc ions and Sulphate ions? It may be a complex compound for all we know, containing multiple anions and cations.

 

[wooowooowoo]

Hmmm
Are you supposed to say it's ZINC SULPHATE or that the compound contains Zinc ions and Sulphate ions? It may be a complex compound for all we know, containing multiple anions and cations.

Possibly. I don't think they will cut marks as long as Sulphate is there

 

[wooowooowoo]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s04_qp_6.pdf

Q4)b)ii)

Solid A's temperature is increasing in the graph - Exothermic
Solib B's temperature is decreasing in the graph - Endothermic

 

[thats_me]

HCl
The reaction is:
HCl + KOH -> KCl + H20
So one mole of KOH is needed for each mole of HCL
So that means the number of moles of KOH in 25cm3 KOH is the same as the number of moles of HCl in 19cm3 of HCl
The HCl is more concentrated because it has the SAME number of moles in a smaller volume. Concentration = No. of Moles divided by volume, so the lower the volume the higher concentration. Alternatively you could think of it as the same number of moles packed in a smaller space (volume)

yesss this was the ques ohkaayee so its like the one that has less volume has high conc if same mole right?