Tips for Chemistry Practicals (P3)

[MindStealth]

wen r u uploading pics? thank u for d tipsss

I really wanted to upload them but my scanner is not working :/
Anyways I'll try to upload them before the paper somehow.

 

[confused_soul]

dude can u take please pics ?
thanksss

 

[melly713]

• Some solutions need shaking to mix them and sometime you will need to shake it really hard to work it out. Just wash your hands and close the top of the test-tube with your thumb and shake.

arent some substances in d test tube corrosive ? i dnt think this is a good idea...

 

[Mustehssun Iqbal]

arent some substances in d test tube corrosive ? i dnt think this is a good idea...

I know. Most of the things in our lab are diluted too.

 

[MindStealth]

arent some substances in d test tube corrosive ? i dnt think this is a good idea...

They will never give you something that can hurt you.
Even when an experiment involves a little harmful gases like SO2, they give you a warning.
So there is no hazard in doing so. Most of the solutions they give you are probably so dilute that you can even drink them...don't try to drink them though.

 

[Amaryllis]

thanks for the tips...but i need some notes for mole calculations please.

 

[Muffy94]

pls upload the pics and notes on moles calculations....
p.s thnx for the awesome tips......
they r really helpful........

 

[CaptainDanger]

You need to get at least two titres within 0.1 cm^3 of one another. For instance, if you get 23.50 and 23.60 or 23.50 and 23.55, that's all right. But a difference greater than that isn't considered an accurate titration for a burette.

23.55? How are you taking that reading from the burette? It can only come in average...???

 

[toxicdevil]

Can we get ORGANIC questions in the Practical?

I have done 2,4 DNPH and tollens test in the Lab.

 

[CaptainDanger]

Can we get ORGANIC questions in the Practical?

I have done 2,4 DNPH and tollens test in the Lab.

Yes it can come...

 

[abcde]

23.55? How are you taking that reading from the burette? It can only come in average...???

A burette has an accuracy of 0.05 cm^3. The graduations are after every 0.10 cm^3 but you can read up to an accuracy of 0.05 cm^3.
So the maximum accepted error in the titre is 0.10 cm^3 and that's how close the two readings we pick should be.

 

[MindStealth]

Can we get ORGANIC questions in the Practical?

I have done 2,4 DNPH and tollens test in the Lab.

I remember one paper too where they asked to test for Aldehyde and Ketone, but I don't think it was a recent one.

 

[Mustehssun Iqbal]

Can someone pls outline how to perform titrations and volumetric analysis?? And which indicators to use?? It will all be a good revision too Inshallah.

 

[smartangel]

guys can you tell me the erorrs..like burrete, pipette, measuring cylinder..

 

[perkypearl]

Its not really a big problem in the recent exams because the only gas you have to identify by smelling is ammonia and if someone has done experiments involving ammonia he will be aware of its smell. Still a good point though but you just need to remember the pungent smell of ammonia, if some other gas has to be identified it will be either mentioned in the paper of the smell or it will have a color.

and if we don't know wt is smell of ammmonia :/ and any goood notes for moles calculations ??

 

[Mustehssun Iqbal]

How to calculate/ measure residual FA1??
http://www.xtremepapers.com/papers/...d AS Level/Chemistry (9701)/9701_s04_qp_3.pdf

 

[Mustehssun Iqbal]

and what is residual FA1 in that question??

 

[perkypearl]

and what is residual FA1 in that question??

after we transfer all the the content there will some stuck to the walls of test tube we have to measure tht mass on balance

 

[Mustehssun Iqbal]

after we transfer all the the content there will some stuck to the walls of test tube we have to measure tht mass on balance

yes I got the answer moments ago. btw thanks loads

 

[perkypearl]

yes I got the answer moments ago. btw thanks loads

ur welcome ... how r u guys preparing for practical ?