Physics, Chemistry and Biology: Post your doubts here!

[Ahmed Khider]

Yes, I got it. It is not so difficult after all. So lead iodide is insoluble?

Yes it is

 

[Yousif Mukkhtar]

Yes it is

Thanks.

 

[Yousif Mukkhtar]

I have a doubt in 15
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w08_qp_1.pdf

 

[always-smile :)]

I have a doubt in 15
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w08_qp_1.pdf

its an endothermic reaction so the temp decrease
so when using 1000 change in temp is 10 when reducing it to 500 the change in temp is doubled so 20 and as it is an endothermic reaction so decrease by 2o ... hope i helped

 

[Rahma Abdelrahman]

is neurone a tissue or organ ??
and is a vein an organ ??

A neurone IS another name for a nerve cell.
If you mean the vein in a plant then it is a tissue.
Vein in an animal (the blood vessel) is an organ.
Wish this helps!

 

[joulie]

look at the image the heart is there 2 so viens and arteries are part of the same oran system ( talking about the circulatory system all ) .... if u didn't got it ask again

well i didn't get it yet
so veins and arteries are tissues but together they are an organ ? or what

 

[Yousif Mukkhtar]

its an endothermic reaction so the temp decrease
so when using 1000 change in temp is 10 when reducing it to 500 the change in temp is doubled so 20 and as it is an endothermic reaction so decrease by 2o ... hope i helped

Yup I got it. Thanks.

Because the solid is now more concentrated.

 

[joulie]

A neurone IS another name for a nerve cell.
If you mean the vein in a plant then it is a tissue.
Vein in an animal (the blood vessel) is an organ.
Wish this helps!

yes thaks alot

 

[Rahma Abdelrahman]

plz help in biology november 2004 Q 8
why the answer is organ system i mean isnt it supposed to be organ as each vein an artery is a tissue so they all make an organ not an organ system

Each blood vessel is an organ.

 

[joulie]

i have a doubt in bio may 2011 Q 11
how come it is D i thoght it is B because the pollen tube is coming from the anther and
Q 19 i know anopheles is a ninsect because it has wings but which is the other insect

 

[always-smile :)]

well i didn't get it yet
so veins and arteries are tissues but together they are an organ ? or what

vein and artery are organs together with the heart they form and organ system so they r parts of an organ system

 

[Rahma Abdelrahman]

TO EVERYONE: IF YOU ARE NOT SURE OF AN ANSWER, PLEASE DON'T CONFUSE OTHERS! PLEASE!

 

[always-smile :)]

TO EVERYONE: IF YOU ARE NOT SURE OF AN ANSWER, PLEASE DON'T CONFUSE OTHERS! PLEASE!

and don't ever try to revise ur paper after u finished answering it EVER

 

[Abu mota]

and don't ever try to revise ur paper after u finished answering it EVER

why??? i do that everytime what is the problem with that? u have to learn from ur mistakes otherwise there will be no use in doing the papers :/

 

[Abu mota]

Each blood vessel is an organ.

no thats wrong one vein is a tissue and one artery is a tissue but many arteries form an organ and many veins form an organ, but many veins and arteries and the heart form the organ system. ty just like just smile said

 

[always-smile :)]

why??? i do that everytime what is the problem with that? u have to learn from ur mistakes otherwise there will be no use in doing the papers :/

i mean in the exam .... cause the main aim from p1 is to confuse u so when u revise it again if any doubt happened all the information u have will disappear and u will find urself changing all ur answers

 

[Abu mota]

OK guyz im off to watch germany vs portugal. GO GERMANY!!!

 

[Ahmed Khider]

well i didn't get it yet
so veins and arteries are tissues but together they are an organ ? or what

No they are not organs..they are tissues but in this diagram they are connecting different organs who are part of the same organ system.

 

[always-smile :)]

No they are not organs..they are tissues but in this diagram they are connecting different organs who are part of the same organ system.

the diagram is only about the circulatory system guys nothing connecting with any other organes

 

[za Shadow]

yea Q.22 is quite tricky the answer is A because if u know from the analysis table if u add silver nitrate to chloride ions u get a white precipitate silver chloride
Q.26 it is C actually D is wrong the ms is wrong
for J04 Q.19 it is A because aluminium and zinc give the same result with sodium hydroxide ( a soluble white ppt) so u cant seperate them but Ammonia for aluminium it forms an insoluble white ppt and zinc is a soluble ppt and so u can seperate them
for Nov 07 carbon is oxidised to carbon dioxide which escapes causing a decrease in mass, while copper when oxidised will form copper oxide which is a solid that settles causing an increase in mass
for Nov 09 i dont know which variant u didnt say i assumed it is variant 1, it is A because the Q says which can be correct and if u started with an element in group 0, then the other element will be in the same group and it will be unreactive and so the answer is A

- well AGCL is white,they consider it not coloured..Whenever asked for a coloured compound,choose the transition metal one.
-Highly reactive metals don't occur as oxides they occur as chlorides..
-It cleraly states differntiate,..If you used NaOH,then you'll get for both white precipitate and both ppt dissolve in excess.While using ammonia solution,NH4OH,one will dissolve in excess the other won;t
-Since carbon reacts with oxygen to form carbon dioxide which is a gas and so will pass out of the tube and mass decreases..Copper forms a solid oxide which is CuO.
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THANK U SOOOOOOOOOOOOOOOO MUCH 4 UR EFFORTS