Physics, Chemistry and Biology: Post your doubts here!

[Lost_Life]

Question 9 ... ON 2007
Chemistry paper 1
CAN ANYONE HELP ME
And can anyone help me to know when to use pipette and burette (like 50cm3)
MJ 2007
Question 37
chemistry .. DOESN'T ADDING BROMINE TO ETHENE INVOLVE A CATALYST (HALOGINATION)
ON 2006 question 37 HOW IS IT A NOT B???

 

[FATIMAH]

they do write it when it absorbs co2, don't dey?

NO NOT ALWAYS !!!!

 

[The sun]

I have got some doubt in Chemistry(0620) Paper-1 Nov.1997 Q3o and June 2004 Q29 Can somebody help me plzzzzz?!

 

[za Shadow]

heeeeeeeeeellllllp meee plzzzzzzzzzzz
plzzzzz explain the opening and closing of stomata in details (when is it) i know nothing about it so plzzzzzz help me

nov03 13 why B it should be A or C i don't understand what does B mean

J 04 40 why A ... B is also correct and the question says "at the bottom of the garden" so its moving towards B

J 06 12 why D not A

nov 08 3) why D it should be B

nov 09 9) i think all the choices are wrong y is D the correct one?????

J11 P11 Q26 i don't understand the Q at all and i think all answers r wrong
Q27 A is also correct so y B

nov 11 P12 Q16 y C not B?????????

PLLLLLLLLLLZZZZZZZZZZZZZZZZ HELLLLLLLLLLLLLLLLLPPPPPPPPPPPPP MEEEEE!!!!!!!!!!! I NEEEEEEEEDDDDDDDDD UUUUUU PLZZZZZZZZZZZZZZ

 

[FATIMAH]

 

[Abu mota]

Question 9 ...ON 2007
Chemistry paper 1
CAN ANYONE HELP ME
And can anyone help me to know when to use pipette and burette (like 50cm3)
MJ 2007
Question 37
chemistry .. DOESN'T ADDING BROMINE TO ETHENE INVOLVE A CATALYST (HALOGINATION)
ON 2006 question 37 HOW IS IT A NOT B???

Q.9 in O/N 07 is D because barium sulfate is an insoluble salt and the B and C arent salt at all but potassium sulfate is the only soluble salt.
Q.37 M/J 07 is C because only adding steam rquires a catalyst but the adding bromine doesnt.
Q.37 O/N 06 doesnt open on xtremepapers :/

 

[always-smile :)]

View attachment 12496

22- the glocuse conc. is controlled by the liver so its not directly connected with the nervous system ( the nervous give order to the liver not to the glucose conc. )
23 its a trick : he made a long story just to confuse u - half the leaves have the allele wich prevent green colour and the other half have the allele which makes the green colour
the leaves collected and kept in dark are all with the allel which prevent green colour so keeping the leaves in light won't make any difference so it will be zero green leaves
hope i helped .. if u didn't get it feel free to ask

 

[sma786]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_qp_11.pdf
Question 9, why would the electrodes be of platinum ? :\ arent they supposed to b made of copper?

 

[Maz]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_qp_11.pdf
Question 9, why would the electrodes be of platinum ? :\ arent they supposed to b made of copper?

Well, the question says inert electrodes, copper isn't inert, platinum is. So, the correct response is B.

 

[Abu mota]

heeeeeeeeeellllllp meee plzzzzzzzzzzz
plzzzzz explain the opening and closing of stomata in details (when is it) i know nothing about it so plzzzzzz help me

nov03 13 why B it should be A or C i don't understand what does B mean

J 04 40 why A ... B is also correct and the question says "at the bottom of the garden" so its moving towards B

J 06 12 why D not A

nov 08 3) why D it should be B

nov 09 9) i think all the choices are wrong y is D the correct one?????

J11 P11 Q26 i don't understand the Q at all and i think all answers r wrong
Q27 A is also correct so y B

nov 11 P12 Q16 y C not B?????????

PLLLLLLLLLLZZZZZZZZZZZZZZZZ HELLLLLLLLLLLLLLLLLPPPPPPPPPPPPP MEEEEE!!!!!!!!!!! I NEEEEEEEEDDDDDDDDD UUUUUU PLZZZZZZZZZZZZZZ

O/N 03 Q.13 doesnt open on xtremepapers
J 04 Q.40 it isnt B because the direction of the flow is away from the garden so the sewage cant come back to the garden
J 06 Q.12 it cant be A because there is a shape of a graph which u have to memorize and also when you increase the temperature from 20 to 30 the rate shud increase but it decreased at A.
nov 08 it shows half of the flower and so shows half the number of stamens, which means it has more than 4 stamens
nov 09 it is D because circulating the blood mains a steep diffusion gradient, thats why our body keeps on pumping blood, every second.
J 11 doesnt open
N 11 glycogen's basic units are glucose not fatty acids, it is clearly C because oil is the same as fats, and fats monomers are fatty acids and glycerol.
ur questions all need studying not explaining :/

 

[Abu mota]

View attachment 12496

for Q.22 if u looked carefully u will see that they are all muscles and so they are affected directly either conract or relax, however at A they are not controlled by muscles it tells the liver to release the hormones, so this is the only one not affected directly.
for Q.40 u need to add the numbers of leaves on the lit part and u will find that they are 430 and the other is 405 and so they are approximately the same (experimental error) so there is no actual green leaves at all.

 

[FATIMAH]

heeeeeeeeeellllllp meee plzzzzzzzzzzz
plzzzzz explain the opening and closing of stomata in details (when is it) i know nothing about it so plzzzzzz help me

nov03 13 why B it should be A or C i don't understand what does B mean

J 04 40 why A ... B is also correct and the question says "at the bottom of the garden" so its moving towards B

J 06 12 why D not A

nov 08 3) why D it should be B

nov 09 9) i think all the choices are wrong y is D the correct one?????

J11 P11 Q26 i don't understand the Q at all and i think all answers r wrong
Q27 A is also correct so y B

nov 11 P12 Q16 y C not B?????????

PLLLLLLLLLLZZZZZZZZZZZZZZZZ HELLLLLLLLLLLLLLLLLPPPPPPPPPPPPP MEEEEE!!!!!!!!!!! I NEEEEEEEEDDDDDDDDD UUUUUU PLZZZZZZZZZZZZZZ

-----> A is not correct b/c if photosynthesis cannot take place b/c it not photosynthesis which keep the plant turgid !!it only provide it with growth and it cannot be C b/c transpiration occurs from both the stem and leaves and so if it was the reason then stem will not be upright
----->B cannot be correct b/c they show the direction of water flow . water from the sewage work is not going back to garden. the water which is flowing near the garden is coming with the factory wasste in it

------> in nov 08 it is written that the diagram shows half flower so see this


-------> IN NOV 09 , D IS CORRECT B/C IT MEANS THAT IT MAINATINS DIFFUSION GRADIENT. THE BLLOD TAKES AWAY THE OXY BLOOD SO THAT ALWAYS THE BLODD HAS LOW CONC OF O2 THEN THE LUNGS

------>IN JUNE 11 Q 26 THEY ARE ASKING THAT Which line correctly shows the path that was taken by a pollen tube to an ovule? SO IT SHOULD BE FROM THE STIGMA
IN A IT IS FROM THE STALK
IN B IT IS FROM THE FILAMENT
IN C IT IS FROM OUTSIDE THE FLOWER
IN D IT IS FROM THE STIGMA

........> IN 27 A IS NOT CORRECT !! IT DOESNOT PASS FAECES TO MOTHER !! FAECES ARE SOLID (LOL) IT ONLY PASS WASTE MATERIAL LIKE CARBONDIOXIDE.. FAECES ARE A FORM OF EGESTION

........> IN NOV 11 IT IS NOT B B/C FATTY ACIDS ARE THE BASIC UNITS OF FATS NOT GLYCOGEN....GLYCOGEN IS THE COMPLEX FORM OF GLUCOSE

HOPE IT HELPED! IF U DIDNT UNDERSTAND STILL FEEL FREE TO ASK

 

[Yousif Mukkhtar]

Guys if we were asked for the graphs for enzymes based on temperature and Ph are these correct.

 

[Ahmed Khider]

Guys if we were asked for the graphs for enzymes based on temperature and Ph are these correct.

They seem correct to me.

 

[The sun]

Guys if we were asked for the graphs for enzymes based on temperature and Ph are these correct.

The enzyme curve based on temperature reaches optimum and then falls steeply (nearly as straight line) and yeah the pH graph is correct

 

[thats_me]

Guys if we were asked for the graphs for enzymes based on temperature and Ph are these correct.[/quoteI think temp will be this way

 

[JOEJOE]

I have got some doubt in Chemistry(0620) Paper-1 Nov.1997 Q3o and June 2004 Q29 Can somebody help me plzzzzz?!

for MJ 2004

Q29 ans is C

30cm3 is used up which is oxygen which makes up 21% of the air
The rest is nitrogen c02 watervapour and noble gases.. these all are 79%

So if 21% = 30cm3

then how much is 100% ( all the volume of the oxgen and other gases)

Do cross multiplication u will get 142 (this is because 21% is only an estimate it might vary) so 150cm3 is the most reasonable answer so choose it

 

[Abu mota]

does anyone have may/june 1998 for biology on free exam papers it isnt complete :/, or can anyone write for me Q.18,19,20,21 because they arent available at free exam paper plz and ty

 

[Abu mota]

i also need help in may/june 1998 Q.36 i did it correct C but imnot sure why, can anyone plz explain it.

 

[AAnsarii]

22- the glocuse conc. is controlled by the liver so its not directly connected with the nervous system ( the nervous give order to the liver not to the glucose conc. )
23 its a trick : he made a long story just to confuse u - half the leaves have the allele wich prevent green colour and the other half have the allele which makes the green colour
the leaves collected and kept in dark are all with the allel which prevent green colour so keeping the leaves in light won't make any difference so it will be zero green leaves
hope i helped .. if u didn't get it feel free to ask

wont d green clr b absent coz there's no light?