ANSWERING ALL BIO/CHEM PAPER 1 DOUBTS :)

[kareem1997]

NOV 08 PAPER 1 QUESTION 13

 

[salvatore]

It's obvious that this reaction is not a redox reaction…And that's why the oxidation state of the CHROMIUM doesn't change…If it was about te chromate then the oxidation state will also be -2 in both cases…THE PH OF the mixture increases since excess alkali is added…

Thanks mahn..

 

[Skynox]

NOV 08 PAPER 1 QUESTION 13

You should already know that the electrolysis of any aquesous solution (except Copper) doesn't produce the metal at the cathode.Instead,hydrogen gas is produced.Since the question stated that it is extracted by electrolysis,therefor the only two available are molten sodium bromide and molten lead bromide.Since,it is low in the reactivity series then it is obviously lead.
salvatore Anytime

 

[balloonsandhighlighters]

Hi ok my doubt is june 2004 question 30.

The answer is C.

I don't understand how the answer is obtained as we are not told what they're seperating.... pls can u explain this to me? Thanks a lot

Also, what is the distillate? Is it water?

Also the same paper question 36. The answer is D. How and why lol ;/ Thanks

 

[saroooor]

Hi ok my doubt is june 2004 question 30.

The answer is C.

I don't understand how the answer is obtained as we are not told what they're seperating.... pls can u explain this to me? Thanks a lot

Also, what is the distillate? Is it water?

Also the same paper question 36. The answer is D. How and why lol ;/ Thanks

Q: 30 - The Ph of the solution left in the flask is alkali , so eventually it will have a high pH . COMPARED to the distillate which is on the other side it is higher . And you know that the only way to Separate The Na from NAOH is by electrolysis . So it seems we are separating the water . So it will be lower . According to my way of thinking .... still you could have another point of view.
Q-36 When you decompose any carbonate you get a metal oxide and carbon dioxide . So here ... Calcium carbonate is decomposed to calcium oxide and carbon dioxide .

 

[Toomuch1995]

here http://www.xtremepapers.com/community/threads/paper-1-bio-1996-onwards.17203/#post-314340

Thank you So much will remember u in my prayers

 

[kareem1997]

THNX BRO

 

[zaid1q]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_11.pdf Q19?!

 

[thats_me]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_11.pdf Q19?!

look..
The alloy contains zinc & copper ,Zinc is oxidised to zinc oxide
When sulphuric acid is added ,zinc oxide would react but copper metal being less reactive than hydrogen cannot react
so it's B (copper has a pink/ brown colour)

 

[balloonsandhighlighters]

th

Q: 30 - The Ph of the solution left in the flask is alkali , so eventually it will have a high pH . COMPARED to the distillate which is on the other side it is higher . And you know that the only way to Separate The Na from NAOH is by electrolysis . So it seems we are separating the water . So it will be lower . According to my way of thinking .... still you could have another point of view.
Q-36 When you decompose any carbonate you get a metal oxide and carbon dioxide . So here ... Calcium carbonate is decomposed to calcium oxide and carbon dioxide .

thank you very veyr muchhh!!!

 

[Toomuch1995]

I practiced many papers and I always get 29 and 28 only. {FAIL ME}

I want someone to explain me those in detail please...?

1) From May/June 2004 (Question 11 and 32).

2) From October/November 2007 (question 5, 15, 25, 28 and 34) .

3) From May/June 2007 (Question 15 , 18 and 17).

4) From October/November 2006 (Question 2 and 28).

5) From May/June 2006 (Questions 34 and 39).

 

[IsraJ]

I practiced many papers and I always get 29 and 28 only. {FAIL ME}

I want someone to explain me those in detail please...?

1) From May/June 2004 (Question 11 and 32).

2) From October/November 2007 (question 5, 15, 25, 28 and 34) .

3) From May/June 2007 (Question 15 , 18 and 17).

4) From October/November 2006 (Question 2 and 28).

5) From May/June 2006 (Questions 34 and 39).

which subject? chem or bio?

 

[Toomuch1995]

Biology

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Biology

Assalam-o-alaikum wr wb...

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Biology

I tried my best to clear your doubts...if still you need any help you are free to ask

 

[Student of the year]

Feel free to ask for anything
Best of luck to all of you !

could u plz explain how d ans to q:16 of w10_12 is B,
& q:32 of w11_12.

 

[Student of the year]

Assalam-o-alaikum wr wb...
View attachment 12391View attachment 12392View attachment 12393View attachment 12394View attachment 12395View attachment 12396View attachment 12397View attachment 12398View attachment 12399View attachment 12401

for d q18 which u answered i have an additional point: the plant wilts meaning more water loss which could be from stomata & stomata only open in light.
(do reply whether its right)

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

for d q18 which u answered i have an additional point: the plant wilts meaning more water loss which could be from stomata & stomata only open in light.
(do reply whether its right)

umm...yeah i 'guess' it's correct

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

could u plz explain how d ans to q:16 of w10_12 is B,
& q:32 of w11_12.

bio or chemistry?

 

[Student of the year]

bio or chemistry?

chemistry