If you have any question on chem p6 im ready you guys. Don't Worry!!

[JimmyCarter]

anytime ONE FOR ALL AND ALL FOR ONE

 

[Lyfroker]

JimmyCarter cn u plz explain q#5 p6 may june 2006

 

[MERIHAN]

Hi.

when in a question they use a measuring cylinder and then later on they ask you how to make the experiment more accurate you say use a burette instead of a measuring cylinder because it is more accurate. I dont think theres a defined range of volumes, u dont need to know that
(pipette holds exactly 25cm cubed)

i did one question now and the question was

Name the piece of apparatus used to measure 25 cm `3 of nitric acid

the answer was measuring cylinder ........ not pipette

 

[JimmyCarter]

JimmyCarter cn u plz explain q#5 p6 may june 2006

Alright, so(all the tests are made on the zinc containing substance since it dissolves in water and they are testin gon the filterate), it contains zinc, therefore when you add NaOHaq to zinc you get a white precipitate that dissolves in excess. Also, when ammonia is added to zinc, a white precipitate forms that is soluble in excess. and when you add barium nitrate a white ppt forms this indicates the presence of a sulfate ion because barium sulfate is a white insolube ppt. test iv shows that it contains no halogens.
Tests on the residue means on the part that doesnt dissolve and tests indicate that the gas produced was CO2 so the ion must have been a carbonate.
the first test a) indicates that it is hydrated since it produced water vapor
this will help you alot http://library.thinkquest.org/2923/tests.html

 

[Lyfroker]

Alright, so(all the tests are made on the zinc containing substance since it dissolves in water and they are testin gon the filterate), it contains zinc, therefore when you add NaOHaq to zinc you get a white precipitate that dissolves in excess. Also, when ammonia is added to zinc, a white precipitate forms that is soluble in excess. and when you add barium nitrate a white ppt forms this indicates the presence of a sulfate ion because barium sulfate is a white insolube ppt. test iv shows that it contains no halogens.
Tests on the residue means on the part that doesnt dissolve and tests indicate that the gas produced was CO2 so the ion must have been a carbonate.
the first test a) indicates that it is hydrated since it produced water vapor
this will help you alot http://library.thinkquest.org/2923/tests.html

thnx a loooooooot!

 

[jaida al hinai]

organic chemistry is not included in p.6 right?

 

[Yousif Mukkhtar]

There is no organic Chemistry.

By the way guys, can anyone explain to me the test for hydrogen? Do we just say pops with a lighted splint?

 

[JimmyCarter]

organic chemistry is not included in p.6 right?

no not really, just the basic stuff like the test for alkenes and alcohols

 

[JimmyCarter]

you are more than welcome, Im glad you understand it now

thnx a loooooooot!

 

[JimmyCarter]

There is no organic Chemistry.

By the way guys, can anyone explain to me the test for hydrogen? Do we just say pops with a lighted splint?

when you expose hydrogen to a lighted splint it burns with a squeaky pop. Thats it. your not required to know more

 

[Yousif Mukkhtar]

when you expose hydrogen to a lighted splint it burns with a squeaky pop. Thats it. your not required to know more

So Hydrogen burns with a pop sound when a lighted splint is brought near.

Thanks.

 

[Hamzeh S]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_S08_qp_6.pdf
q4 E first part it ask which volume of potassium manganate was used the greatest and it said that the solution already had 25cm3 of salt and it became 26 so only 1 cm was added ! :S but it say that the volume added 26 in the mark scheme :S help plz

 

[jaida al hinai]

whts the test 4 sodium nitrate solution?

 

[JimmyCarter]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_S08_qp_6.pdf
q4 E first part it ask which volume of potassium manganate was used the greatest and it said that the solution already had 25cm3 of salt and it became 26 so only 1 cm was added ! :S but it say that the volume added 26 in the mark scheme :S help plz

the 25cm3 is for the salt but they asked for potassium manganate. what you do is that you compare the difference of the two experiments that you should have entered in the table and the greatest difference means that it used the greatest volume. understand?

 

[Srhmnir]

thanx a lot everyone !! you really helped me
my paper is 61 tomorrow ! hope we all do well
best of luck for every one

 

[Lost_Life]

YA RAB WE ALL GET A*'S

 

[JimmyCarter]

whts the test 4 sodium nitrate solution?

well thats a pretty complicated one, but ok. So you can do a flame test an orange/yellow flame is made this indicates the presence of Sodium. then add NaOH and aluminum powder and heat, a gas that has a pungent smell and turns indicator paper blue (ammonia) proves the presence of Nitrates

 

[JimmyCarter]

YA RAB WE ALL GET A*'S

إن شاء الله‎

 

[jaida al hinai]

well thats a pretty complicated one, but ok. So you can do a flame test an orange/yellow flame is made this indicates the presence of Sodium. then add NaOH and aluminum powder and heat, a gas that has a pungent smell and turns indicator paper blue (ammonia) proves the presence of Nitrates

0_O.... thx

 

[JimmyCarter]

0_O.... thx

hahahh ur welcome