IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => GCE AS & A2 Level => Queries => Topic started by: coatseville on May 14, 2010, 09:59:24 am

Title: Chemistry Unit 3b As exam..
Post by: coatseville on May 14, 2010, 09:59:24 am

How did you find it?
24 hours has passed!

Title: Re: Chemistry Unit 3b As exam..
Post by: Saladin on May 14, 2010, 10:14:51 am

OKish

it was not that easy.

Title: Re: Chemistry Unit 3b As exam..
Post by: coatseville on May 14, 2010, 10:45:53 am

Yah =(
Question 1 was quite confusing i think..
Oh and what was you % purity?

Title: Re: Chemistry Unit 3b As exam..
Post by: Saladin on May 14, 2010, 10:48:09 am

I think I got 9.8%.

Title: Re: Chemistry Unit 3b As exam..
Post by: coatseville on May 14, 2010, 11:00:07 am

Oh okay yeah thats different than mine i got 98.4%

Title: Re: Chemistry Unit 3b As exam..
Post by: Meticulous on May 14, 2010, 11:01:47 am

Youre right coat. Trust me

Title: Re: Chemistry Unit 3b As exam..
Post by: coatseville on May 14, 2010, 11:07:17 am

oh thanks :)

Title: Re: Chemistry Unit 3b As exam..
Post by: M-H on May 14, 2010, 11:47:53 am

good...really good paper:)

Title: Re: Chemistry Unit 3b As exam..
Post by: Book lover22 on May 14, 2010, 04:03:31 pm

Salamzz!

It was a tricky paper like u had 2 think hard! not da typ dat da answer cums wid da flow!
nway only few doubts:

1.wat was da colour change 4 da starch indicator?
2.wat was da test 4 da OH- ion?

Title: Re: Chemistry Unit 3b As exam..
Post by: coatseville on May 14, 2010, 04:52:23 pm

The colour change was from blue to colourless
and the OH test is add phosphorus pentachloride and hydrogen chloride (steamy fumes) given off!

Title: Re: Chemistry Unit 3b As exam..
Post by: Book lover22 on May 15, 2010, 09:27:36 am

but isnt dat 4 organic compounds only? :S

i wrote test da solution with red litmus paper it will turn blue...hows dat?

Thanks...

Title: Re: Chemistry Unit 3b As exam..
Post by: lupilipid on May 15, 2010, 07:36:30 pm

I got percentage purity as 60% and the starch indicator was iodine (makes sense right?)

Title: Re: Chemistry Unit 3b As exam..
Post by: coatseville on May 15, 2010, 08:23:34 pm

Im not sure about the OH test group but thats just what I think...
Erm i dont remember the question what did it say about the starch?