Physics, Chemistry and Biology: Post your doubts here!

[Abu mota]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Biology (0610)/0610_s09_qp_1.pdf
q 16, what's C?

C is the xylem vessel, the right answer is B because water leaves only from the stomata

 

[Abu mota]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_qp_11.pdf
plz xplain q 25
also q3
thx

Q.3 the residue is used to describe insoluble and filtrate is used to describe that it is soluble and it formed a residue in ethanol but formed a filtrate in water so the answer is B
Q.25 the answer is D because brass doesnt have a chemical formula and only zinc reacts with hydrochloric acid, copper doesnt

 

[Ahmed Khider]

w04 Q.32 in the mark scheme it says it is D but imnot convinced, isnt the zinc just covering the iron and doesnt make a part of its composition?

Just think about D is the only choice where iron is covered with zinc!!

 

[Abu mota]

Just think about D is the only choice where iron is covered with zinc!!

I don't think you understood me, it says in the question composition I.e what it's made of and when it's galvanized it is just covered with zinc and not made up of zinc :/

 

[Ahmed Khider]

I don't think you understood me, it says in the question composition I.e what it's made of and when it's galvanized it is just covered with zinc and not made up of zinc :/

Well definitely the amount of iron in this question will be much more than the amount of zinc..thats how i thought about it if u still didnt understand u might wanna ask some1 else

 

[Maz]

I don't think you understood me, it says in the question composition I.e what it's made of and when it's galvanized it is just covered with zinc and not made up of zinc :/

Composition does not refer to the composition of the compound unless stated eg. the composition of iron oxide is iron and oxygen. In this q. composition merely means what it is made of.

 

[AAnsarii]

do v need 2 learn clr of ions or sth 4 mcq's? like in w10_11 q19

 

[Abu mota]

do v need 2 learn clr of ions or sth 4 mcq's? like in w10_11 q19

Yes u do

 

[AAnsarii]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w10_qp_11.pdf
q 30, shouldn't d ans b carbon, coz CO reduces iron oxide?

 

[Abu mota]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w10_qp_11.pdf
q 30, shouldn't d ans b carbon, coz CO reduces iron oxide?

It didn't say iron oxide it said impure iron i.e pig iron which is turned into steel by adding oxygen and calcium oxide that neutralises the acidic impurities so the answer is calcium

 

[Ahmed Khider]

It didn't say iron oxide it said impure iron i.e pig iron which is turned into steel by adding oxygen and calcium oxide that neutralises the acidic impurities so the answer is calcium

Ready for paper 1??U look like an A* student to me

 

[joulie]

can someone explaine me these:-
biology june 1999 Q 26 i know it is mitosis but why cell enlargment
nov 2000 Q24 why did the plemule bend upward though there os no light
nov 1998 Q 10 why isn't the answer bile and
q 11 why is itt ph 8 not 7

 

[Maz]

can someone explaine me these:-
biology june 1999 Q 26 i know it is mitosis but why cell enlargment
nov 2000 Q24 why did the plemule bend upward though there os no light
nov 1998 Q 10 why isn't the answer bile and
q 11 why is itt ph 8 not 7

Firstly, from where in the world did you get such old papers? (please post the link.)
And why are you solving them in the first place. Don't tell me you have completed all the latest ones.

 

[Abu mota]

can someone explaine me these:-
biology june 1999 Q 26 i know it is mitosis but why cell enlargment
nov 2000 Q24 why did the plemule bend upward though there os no light
nov 1998 Q 10 why isn't the answer bile and
q 11 why is itt ph 8 not 7

for june 1999 because the cell need to get bigger and then divide, get bigger and then divide. (imnot very sure of this)
for nov 2000 Q.24 u shud memorize that naturally the plumule has negative geotropism and radicle has positive geotropism and so the answer is C
for nov 1998 Q.10 because bile emulsify the fats they dont digest it only enzymes digest fats or oil into fatty acids or glycerol
Q.11 because of the temperature optimum temperature for enzyme action is 37 degrees Celsius and ph 8 isnot very different from ph 7

 

[Abu mota]

i knew why because growth is defined as the increase in dry mass due to the increase in the number of cells or the size of the cells and now im very sure of this

 

[Rahma Abdelrahman]

A very simple question from me... What is the difference between evaporation and crystallisation... What does one method offer that the other does not? I'm posing this question because both methods of separation seem to satisfy the same objective: extracting a dissolved substance from a solution...

Another difference: Crystallisation forms crystals that are 100% pure, unlike evaporation.

 

[joulie]

Firstly, from where in the world did you get such old papers? (please post the link.)
And why are you solving them in the first place. Don't tell me you have completed all the latest ones.

actualy i've almost completed the recent papers bcuse i finished the other exams since 21 may.

 

[joulie]

i knew why because growth is defined as the increase in dry mass due to the increase in the number of cells or the size of the cells and now im very sure of this

thanks alot inshallah you will get A* cause ur so smart

 

[Abu mota]

Jolie if u have any other questions plz ask I'm kind of bored LOL

 

[Rahma Abdelrahman]

Firstly, from where in the world did you get such old papers? (please post the link.)
And why are you solving them in the first place. Don't tell me you have completed all the latest ones.

Actually, the old questions sometimes repeat themselves in the recent exams!