Chemistry: Post your doubts here!

[daredevil]

may be they assigned some pathan to make the time table

seriously stupid is the king of understatement here!! freakin imbeciles!! I mean come ON!! this is way too much like our exams would be technically half over until the 13th (within 6 days) and then the other half (that really is the prep worth and all) will be after almost more than a month in junE!! :O and the syllabus is still the same!! :O
Hate IT!! >__<

 

[A star]

seriously stupid is the king of understatement here!! freakin imbeciles!! I mean come ON!! this is way too much like our exams would be technically half over until the 13th (within 6 days) and then the other half (that really is the prep worth and all) will be after almost more than a month in junE!! :O and the syllabus is still the same!! :O
Hate IT!! >__<

actually they made this timetable by picking chits from a bowl. xD

 

[megamind]

In HPLC, you have-
1) The stationary phase: a non-volatile liquid. This is packed tightly into a column. This column is a few millimeters in diameter and is up to 30-40 cm long.
2) The mobile phase: usually a polar solvent (it is a liquid) is chosen for the mobile phase. It's usually methanol.

So the mobile phase has to be forced through the columns at high pressures (at about 400 atm). The column provides a large surface area for the partitioning to occur. Partitioning is basically separating the mobile phase into its components. The components are usually detected by measuring the absorbance of ultraviolet radiation through a cell at the end of the column. This data is logged into a computer. The computer then usally form peaks for each component present in the mobile phase. The area under each peak is proportional to the amount of solute particles emerging from the column.

Note: The column for the HPLC is much shorter than the column used in GLC

Hope this helps!

The application booklet says that silica is in the colomn i am not sure if it is the staionery phase or wheter there is a liqiud coated to it,acrs as stationery phase

 

[snowbrood]

how to explain that a compound is cis or trans

 

[snowbrood]

The application booklet says that silica is in the colomn i am not sure if it is the staionery phase or wheter there is a liqiud coated to it,acrs as stationery phase

help

 

[A star]

have made it dont knw how to upload it

 

[Alice123]

have made it dont knw how to upload it

There's this option called 'upload a file'

 

[A star]

There's this option called 'upload a file'

here i didnt see the buttons

 

[A star]

as for explanation add the value of activation energy for the first step as 16 KJ then add the enthalpy change of reaction for the steep drop between propogaton and termination step
you have or can add headings for each which is which propogation waghaira

 

[Alice123]

as for explanation add the value of activation energy for the first step as 16 KJ then add the enthalpy change of reaction for the steep drop between propogaton and termination step
you have or can add headings for each which is which propogation waghaira

Thanks.....

 

[daredevil]

actually they made this timetable by picking chits from a bowl. xD

come on that can't be true... God is never that cruel This datesheet would've been better if it was up to God to decide on the chits Its all their own handiwork

 

[A star]

come on that can't be true... God is never that cruel This datesheet would've been better if it was up to God to decide on the chits Its all their own handiwork

looks like it xD

 

[Executor]

AOA,
Please spare few minutes and go to this thread http://www.xtremepapers.com/community/threads/dua-for-all-candidates.14272/ and make dua for all those currently appearing in the exams. You will also find useful duas in it and Remember every share counts.

 

[PhyZac]

how to explain that a compound is cis or trans

You mean how to know or how to describe??

 

[strangerss]

Any one has 2002 p1 and p2 marking schemes ?

 

[syed1995]

Any has 2002 p1 and p2 marking schemes ?

http://www.freeexampapers.com/#A Level/Chemistry/CIE/

 

[hassankhan]

because chlorine is a strong oxidizing agent so it will be strongly reduced by 2 electrons instead of one. As you go down the halogen group the element becomes less strongly as an oxidising agent and more strong as a reducing agent

Thnks

 

[strangerss]

Thanks a lot , btw there isn't a marking scheme for p1:/

http://www.freeexampapers.com/#A Level/Chemistry/CIE/

 

[hassankhan]

The lattice energy of CuCl2 is more negative than CuCl, (that is more exothermic) therefore more energy is released, therefore more stable and therefore more readily forms.

Sorry for using "therefore" alot!

Thnks man

 

[daredevil]

You won't prepare for physics?

already spent the last three days on it.... now will do some revising before the paper and that's all the time i havve for it the concepts are pretty much covered up i like to think now its just up to the paper to throw watever curve balls it has to and i'll try to give it my best shot
see i had these 9 days set aside before the 7th to prepare for phy chem and maths as they are all in a row one after the other.... for bio i already hav three days so had to do it in these too :