Physics, Chemistry and Biology: Post your doubts here!

[My Name]

To everyone giving the chemistry ATP soon
this might help you for revision
https://www.xtremepapers.com/community/threads/all-things-u-need-to-know-about-chemistry-p6.33395/
Credits to The Chill Master

 

[Mr.Physics]

Just learn tests for ions,gases and colours of some well known elements and compounds .Master the topic of salts and their formation,titration ,crystallization plus electrolysis of HCl and NaCl ,50 % of chemistry ATP will be yours !! the other 50% of the paper will generally be from all other topics !! Practice past papers from 2007-2014 and check your attempts using mark schemes . Do read examiner reports because they mention about the errors and mistakes the students usually make !! In this way , you can take your paper to the degree of perfection (not 100 % but above 95 % ). Hope it helps !!

 

[lina1999]

This is All what you need

Thanks Alot ! THAT WAS VERY HELPFUL

 

[Muaaz Iqbal]

Just learn tests for ions,gases and colours of some well known elements and compounds .Master the topic of salts and their formation,titration ,crystallization plus electrolysis of HCl and NaCl ,50 % of chemistry ATP will be yours !! the other 50% of the paper will generally be from all other topics !! Practice past papers from 2007-2014 and check your attempts using mark schemes . Do read examiner reports because they mention about the errors and mistakes the students usually make !! In this way , you can take your paper to the degree of perfection (not 100 % but above 95 % ). Hope it helps !!

Well From where Can i find Examiner report ?
Are you having any Resource ??

 

[lina1999]

https://docs.google.com/file/d/0B108wb6vqF_8TDZydUdObjVFXzg/edit?pli=1
Maths problem november 2014

 

[Iris Dylan Lane]

A reaction is carried between an acid n metal
If the acid is in excess, will changin concentration of acid have an effect on rate of reaction?

 

[sj0007]

Well From where Can i find Examiner report ?
Are you having any Resource ??

You can find some of them on igcsecentral or any other website where there are all the past papers...............................

 

[sj0007]

Ummmm..............can anyone explain how the answer to this question is C?????

 

[sj0007]

Question?

OMG i literally forgot to post the ques..............sorry

 

[qwertypoiu]

OMG i literally forgot to post the ques..............sorry
View attachment 52262

Leaves will not wilt for sure, because xylem is still fine so water still travels nice and easy from bottom to top through transpiration, the leaves are getting the water they need and the ions dissolved in water as well. This applies to both branches, since xylem is still fine.
As for growth (and repair), the organism requires protein and sugar (for energy to grow) to do that. And to build proteins the plant needs amino acid, which travels through the phloem, and sucrose also travels through phloem. So growth requires phloem. Unlike the xylem, the fluid in phloem may travel in any direction. However, it is the leaves on top that perform photosytnthesis and produce sucrose (source), and give it to other cells (sink). The phloem is gone now, so top leaves can supply for their own branch, but not for bottom.

 

[qwertypoiu]

why can't the bottom leaves photosynthesise?

I think it may have to do with the top leaves blocking the bottom leaves. It says the growth is reduced, not completely stopped.

 

[sj0007]

Leaves will not wilt for sure, because xylem is still fine so water still travels nice and easy from bottom to top through transpiration, the leaves are getting the water they need and the ions dissolved in water as well. This applies to both branches, since xylem is still fine.
As for growth (and repair), the organism requires protein and sugar (for energy to grow) to do that. And to build proteins the plant needs amino acid, which travels through the phloem, and sucrose also travels through phloem. So growth requires phloem. Unlike the xylem, the fluid in phloem may travel in any direction. However, it is the leaves on top that perform photosytnthesis and produce sucrose (source), and give it to other cells (sink). The phloem is gone now, so top leaves can supply for their own branch, but not for bottom.

THANKYOU SOOOOOO MUCH!!!!!!!!!!!!!!!!!!!

 

[qwertypoiu]

THANKYOU SOOOOOO MUCH!!!!!!!!!!!!!!!!!!!

Glad it helped

 

[NOneed2speedd]

Hello friends
can someone clear my confusion. ..
In Q.17 answer in ms is B but i wrote C.. how can carbon be collected over water. . I learned it is collected through downward delivery

And in Q.40 ans in ms is D but I wrote A as ethanol is produced by fermentation then how it is wrong?

 

[qwertypoiu]

Hello friends
can someone clear my confusion. ..
In Q.17 answer in ms is B but i wrote C.. how can carbon be collected over water. . I learned it is collected through downward delivery

And in Q.40 ans in ms is D but I wrote A as ethanol is produced by fermentation then how it is wrong?

As for the first question, pay careful attention to the wording. It says:
"Which apparatus is suitable to collect and measure the volume of carbon dioxide"
The downward delivery tube cannot measure volume, and gas syringe is definitely correct So your answer is B. I'm sorry about all this underlining my phone is going weird.
As for next question, ethanol is NOT unsaturated, so only 1 and 3 are correct, thus answer is C

 

[NOneed2speedd]

As for the first question, pay careful attention to the wording. It says:
"Which apparatus is suitable to collect and measure the volume of carbon dioxide"
The downward delivery tube cannot measure volume, and gas syringe is definitely correct So your answer is B. I'm sorry about all this underlining my phone is going weird.
As for next question, ethanol is NOT unsaturated, so only 1 and 3 are correct, thus answer is C

Thanks for helping and in second question... sorry for my dumbness but hw ethanol is not unsaturated? I mean it doesn't contain double bonds.. ?

 

[masterex567]

Thanks for helping and in second question... sorry for my dumbness but hw ethanol is not unsaturated? I mean it doesn't contain double bonds.. ?

Saturated is single bonds only.
Unsaturated is with double bonds.

thus ethanol is saturated as it doesn't have a double bond, and has single bonds only.

 

[lara dalal]

Hello. Can someone tell me how to calculate this? The answer is D.

 

[NOneed2speedd]

Saturated is single bonds only.
Unsaturated is with double bonds.

thus ethanol is saturated as it doesn't have a double bond, and has single bonds only.

Oh yes just looked at the notes. ... don't know what was going in my mind. .. looks like i m studying too much

 

[NOneed2speedd]

Hello. Can someone tell me how to calculate this? The answer is D.
View attachment 52312