Chemistry Test of Ions

[ThatReallyReallyWeirdDude]

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

Q4)b)ii)

In Experiment 1 it's EXOTHERMIC because it's a line sloping upwards i.e. the temperature increases with time meaning the reaction is producing heat
In Experiment 2, it's a ENDOTHERMIC because it's a line sloping downwards i.e. the temperature decreases with time meaning the reaction is ABSORBING heat from the mixture

 

[ThatReallyReallyWeirdDude]

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

Well
In a nutshell yes I guess, though you should try to understand WHY not just specific cases like this

 

[ThatReallyReallyWeirdDude]

P.S.

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


Q4)b)ii)

I LOVE YOUR SIGNATURE!

 

[ZainH]

In Experiment 1 it's EXOTHERMIC because it's a line sloping upwards i.e. the temperature increases with time meaning the reaction is producing heat
In Experiment 2, it's a ENDOTHERMIC because it's a line sloping downwards i.e. the temperature decreases with time meaning the reaction is ABSORBING heat from the mixture

Wow how didn't I see that.. thanks.

P.S.
I LOVE YOUR SIGNATURE!

Haha, thanks. Your's is pretty funny as well x)

 

[ThatReallyReallyWeirdDude]

Thanks Zain Gotta love Stewie
I give up on trying to beat Wow at getting answers in first ^^
Also, correction, the reaction between ammonia and nitric acid is:
NH4OH + HNO3-> H2O + NH4NO3

 

[ThatReallyReallyWeirdDude]

I actually have a question myself if anyone can answer, but not to do with ions and I doubt it's even in syllabus.
Why does density of group 1 elements decrease down the group? Is it because atoms have larger shells thus in the same volume there's less atoms?
But the fact that the mass of each atom increases downwards as well should mean that it's countered. >.<

 

[ZainH]

Thanks Zain Gotta love Stewie
I give up on trying to beat Wow at getting answers in first ^^
Also, correction, the reaction between ammonia and nitric acid is:
NH4OH + HNO3-> H2O + NH4NO3

Well lets see who answers this first..

Q5)d) Explain this one please..and Q6)b) What test is this? THey just heated copper oxide...how are we supposed to know the color change?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s04_qp_6.pdf

 

[wooowooowoo]

Thanks Zain Gotta love Stewie
I give up on trying to beat Wow at getting answers in first ^^
Also, correction, the reaction between ammonia and nitric acid is:
NH4OH + HNO3-> H2O + NH4NO3

Hahahahaha
I'm so happy there are so many intelligent people in here.

 

[wooowooowoo]

I actually have a question myself if anyone can answer, but not to do with ions and I doubt it's even in syllabus.
Why does density of group 1 elements decrease down the group? Is it because atoms have larger shells thus in the same volume there's less atoms?
But the fact that the mass of each atom increases downwards as well should mean that it's countered. >.<

Go down the group - Increase in mass
Density = Mass/ Volume
So the increase in mass crosses increase in volume and so the denisty increases as we go down

 

[wooowooowoo]

Well lets see who answers this first..

Q5)d) Explain this one please..and Q6)b) What test is this? THey just heated copper oxide...how are we supposed to know the color change?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s04_qp_6.pdf

I'll pass this one. Let weirdude answer it.

 

[ThatReallyReallyWeirdDude]

Well lets see who answers this first..

Q5)d) Explain this one please..and Q6)b) What test is this? THey just heated copper oxide...how are we supposed to know the color change?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s04_qp_6.pdf

Okay then
(iii*) shows that Nitrate is present. It's most likely D since all nitrates are soluble
(v) shows that limewater is present since it turns milky. Limewater is calcium hydroxide.
*Edit
(iv) actually supports (v). Since it's alkaline it supports the theory that calcium hydroxide is present

 

[ThatReallyReallyWeirdDude]

And as for q6b, it'd change from black to reddish-brown, and i'm afraid that's just a case of knowing the colours of copper oxide and copper

 

[Ahmedoo97]

I need an example in the past paper about:
Titration
Neutralization

 

[ThatReallyReallyWeirdDude]

And Woow you're correct, density increases down the group (it's times like this I hate my teacher) though for some reason it goes up at sodium, down again at potassium before going up again.
And I don't think we'll have to explain it *facepalm*
http://www.chemguide.co.uk/inorganic/group1/properties.html

 

[ZainH]

Okay then
(iii*) shows that Nitrate is present. It's most likely D since all nitrates are soluble
(v) shows that limewater is present since it turns milky. Limewater is calcium hydroxide.
*Edit
(iv) actually supports (v). Since it's alkaline it supports the theory that calcium hydroxide is present

Understood everything besides how (iii) shows that nitrate is present..
And for the copper thing, okay.. I'll remember that. Any other colors of metals/oxides I should remember? (That aren't present in tests for anions/cations)

 

[ThatReallyReallyWeirdDude]

Understood everything besides how (iii) shows that nitrate is present..
And for the copper thing, okay.. I'll remember that. Any other colors of metals/oxides I should remember? (That aren't present in tests for anions/cations)

iii)
The test for nitrate is to add sodium hydroxide, aluminium and warm gently. If nitrate is presence ammonia is produced - and you can tell ammonia is produced by the alkaline pH (turns litmus paper blue) AFAIK there are no other alkaline gasses (at least in our syllabus).
So in iii they did the test and ammonia was produced

 

[ZainH]

iii)
The test for nitrate is to add sodium hydroxide, aluminium and warm gently. If nitrate is presence ammonia is produced - and you can tell ammonia is produced by the alkaline pH (turns litmus paper blue) AFAIK there are no other alkaline gasses (at least in our syllabus).
So in iii they did the test and ammonia was produced

AH! Now it makes sense, thanks.
STAY TUNED! I'll be back with more questions x)

 

[wooowooowoo]

AH! Now it makes sense, thanks.
STAY TUNED! I'll be back with more questions x)

Hooray

 

[ZainH]

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

Q8)

 

[NIM]

guys any tip fr chem ...