EDEXCEL AS CHEMISTRY UNIT 3B REVISION NOTES - Wednesday 8th June 2005

3B: LABORATORY CHEMISTRY

a) recognise the results of reactions of compounds specifically mentioned in Units 1 and 2 of the specification and the results of tests for simple ions: carbonate, hydrogencarbonate, sulphate (VI), sulphite, chloride, bromide, iodide, nitrate, ammonium, lithium, sodium, potassium, magnesium, calcium, strontium and barium
b) recognise the chemical tests for simple gases, to include hydrogen, oxygen, carbon dioxide, ammonia, chlorine, nitrogen dioxide and sulphur dioxide
c) describe the techniques used in volumetric analysis and enthalpy change measurements
d) describe the techniques used in simple organic preparations such as distillation and heating under reflux
e) recall and interpret details of the chemistry of the elements and compounds listed in Units 1 and 2 of this specification
• this includes the chemistry of Groups 1, 2 and 7 and the chemistry associated with the organic compounds listed in topic 2.2
f) interpret quantitative and qualitative results
g) devise and plan simple experiments based on the chemistry and techniques summarised in a to e above
h) evaluate error in quantitative experiments
• see Appendix I for material available to assist centres in teaching this area
i) comment critically on information concerning experimental procedures
j) comment on safety aspects of experiments based on supplied data or recall of the chemistry of the compounds listed in Units l and 2. Safety considerations should relate to specific experiments not be of a general nature
• it will be assumed that students wear eye protection during all practical work.

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Here it is, positive rep would be very much appreciated.
I'll edit the document if I find any errors.
That's my C3B revision done.
(I would have included diagrams but the file size was too big)

Good luck everyone! :tsr:

3B - Tests for ions and gases.doc102.4KB

3B - volumetric analysis and enthalpy change.doc41.5KB

3B - Organic procedures.doc34.3KB

3B - continued.doc47.6KB

Reply 1

Asian cutie

1

thank you so much (ps. look at ur rep points!)

Reply 2

Christophicus

OP

18

Asian cutie

thank you so much (ps. look at ur rep points!)

thanks, didn't count though :frown:

First document is the best, the others were rushed.
It didn't take me too long either, about 2 hours.

Reply 3

aranel_rocco

Wow!
Thanks alot!
Those look so amazing, will have to have a good look through them!
Gave ya major rep points!

Reply 4

StyleLover

2

KOOL, Thnks for the Notes WM!!!! :biggrin:

Reply 5

Christophicus

OP

18

StyleLover

KOOL, Thnks for the Notes WM!!!! :biggrin:

No probs. it's excellent revision for me too!

Reply 6

ArVi

13

Wow, thanks alot for these... really needed them!!

Reply 7

Paxi

1

Thanks widow maker ... i haven't revised unit 3 chemistry this year(resitting) so these would be really useful.

Reply 8

Christophicus

OP

18

Lol, someone neg-repped me for this thread, it didn't count though :p:

Reply 9

Christophicus

OP

18

A few revision questions.

1) What is the test for Ba2+?

2) A compound A is warmed with NaOH and then HNO3 and AgNO3 is added to the solution, a yellow precipitate forms. A has three carbon atoms. The precipitate formed was insoluble in concentrated ammonia solution. What is the name of the precipitate? What is the formula of A?

3) Choose the three titres you should average to find the average titre from the following.
23.5, 23.9, 23.4, 22.7, 23.3.

4) What is the test for NO2?

5) What is the test for SO2?

6) How would you distinguish between ethane and ethene?

7) What is the test for a primary alcohol?

Reply 10

mizfissy815

12

Thanx alot Widowmaker...you're a life saver!

Reply 11

Heidi

Thank you so much!!!!!!!!!!!!!!

Reply 12

Christophicus

OP

18

honestly it's no problem. I do it for revision and I may as well post in on here.
I've posted some revision questions above so if you want to post your answers to check if you're right then by all means do.

Reply 13

AtSnIaB-42

If only i'd had these on the day of my practical Exam.

Reply 14

shimmerinapple

6

Widowmaker

A few revision questions.

1) What is the test for Ba2+?

2) A compound A is warmed with NaOH and then HNO3 and AgNO3 is added to the solution, a yellow precipitate forms. A has three carbon atoms. The precipitate formed was insoluble in concentrated ammonia solution. What is the name of the precipitate? What is the formula of A?

3) Choose the three titres you should average to find the average titre from the following.
23.5, 23.9, 23.4, 22.7, 23.3.

4) What is the test for NO2?

5) What is the test for SO2?

6) How would you distinguish between ethane and ethene?

7) What is the test for a primary alcohol?

I'm not sure if the answers are correct but i'll have a go.
1. Flame test --> apple green
2. Silver Iodide, C3H5I
3. 23.5, 23.4, 23.3
4. Warm with HaOH and aluminium(solid), test for gas evolved. If its NO2, the gas should turn red litmus blue (ammonia)
5. Add barium nitrate, white ppt which is does not dissolve in dilute HCL.
6. Add bromine water to both, one should decolourise. That is ethene.
7. Warm with acidified potassium maganate (vi), should show colour change from purple to green. (not sure about this one. Is this just a general test for alcohol or a specific test for primary alcohol?)

Reply 15

Christophicus

OP

18

shimmerinapple

I'm not sure if the answers are correct but i'll have a go.
1. Flame test --> apple green
correct
2. Silver Iodide, C3H5I
correct
3. 23.5, 23.4, 23.3
correct
4. Warm with HaOH and aluminium(solid), test for gas evolved. If its NO2, the gas should turn red litmus blue (ammonia)
Warm what? I think you're getting confused between the gas NO2 and the anion NO3-
5. Add barium nitrate, white ppt which is does not dissolve in dilute HCL.
??? SO2 is a gas
6. Add bromine water to both, one should decolourise. That is ethene.
correct
7. Warm with acidified potassium maganate (vi), should show colour change from purple to green. (not sure about this one. Is this just a general test for alcohol or a specific test for primary alcohol?)
I think the colour change is from purple to colourless but don't quote me on it.
Other valid answer would have been;
add PCL5, white steamy fumes seen.
add acidified dichromate solutiom, solution turns from orange to green.

not bad. Do you want me to type up some more revision questions?

Reply 16

cerebrum_core

1

I have read through it and i think that there is a mistake.

test the halogen in Haloalkanes

You first have to reach the Halogen with NaOH in aqueous solution in order to form the Alcohol and NaX. Then you test NaX with HNO₃ and AgNO₃ .
You cannot test it directly because in the organic molecule the halogen does not excist as an Ion thus it doesn't form a ppt (AgX)
:smile:

Reply 17

Christophicus

OP

18

cerebrum_core

I have read through it and i think that there is a mistake.

test the halogen in Haloalkanes

You first have to reach the Halogen with NaOH in aqueous solution in order to form the Alcohol and NaX. Then you test NaX with HNO₃ and AgNO₃ .
You cannot test it directly because in the organic molecule the halogen does not excist as an Ion thus it doesn't form a ppt (AgX)
:smile:

sorry, which document are you referring to?