Physics, Chemistry and Biology: Post your doubts here!

[EpicLol]

Im on my friedns computer and its horrible... Its not even able to load a question paper

 

[dana xP]

ummmmmmm guys can any body help me plz ?
i want a convincing anwer to 'use the kinetic theory to explain the process of diffusion' !!

 

[imperial]

Im on my friedns computer and its horrible... Its not even able to load a question paper

im completely the opposite case haha, my computer does not load and iam using my friend computer to load the paper.

 

[EpicLol]

im completely the opposite case haha, my computer does not load and iam using my friend computer to load the paper.

lol XD

 

[AAnsarii]

Sn has the variable valencies of 2 and 4.
While, Ag has the variable valencies 1 and 2.

what do v use n how do v noe it?

 

[Maz]

what do v use n how do v noe it?

Usually they would most probably specify what we are supposed to use or we have to deduce it as we did in this question.

 

[AAnsarii]

ummmmmmm guys can any body help me plz ?
i want a convincing anwer to 'use the kinetic theory to explain the process of diffusion' !!

Diffusion is the movement of one kind of particles through another kind due to its kinetic energy (that makes it move).
hope dat helped..

 

[dana xP]

Diffusion is the movement of one kind of particles through another kind due to its kinetic energy (that makes it move).
hope dat helped..

but this question normally would be for 3 marks ,,, so this anwser would be enough !!
but thanx anyway

 

[imperial]

what does the square sign indicates in things like (CH2)2 -CH2-CH3
BREAKING BOND, FORMING BOND, BOND ENERGY AND WHAT IT HAVE TO DO WITH EXOTHERMIC AND ENDOTHERMIC

my unsolved questions remain unsolved, need help

 

[Maz]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s05_qp_3.pdf
2 c) i) What's the reason?

It's zinc and the reason would be since the mass of zinc has become constant, it shows that there is no more iodine to react with the zinc.

 

[AAnsarii]

but this question normally would be for 3 marks ,,, so this anwser would be enough !!
but thanx anyway

dis ans would b enough?

 

[Ibrahim Basar]

Nitrates nitrites... which metals give nitrates and which give nitrites quickly exam is tomorrow!

 

[Maz]

what does the square sign indicates in things like (CH2)2 -CH2-CH3
BREAKING BOND, FORMING BOND, BOND ENERGY AND WHAT IT HAVE TO DO WITH EXOTHERMIC AND ENDOTHERMIC

my unsolved questions remain unsolved, need help

I am sorry i have no answer for the first question.

For the second,
exothermic reactions involve forming bonds. eg freezing of water, where water molecules lose heat energy and bonds are formed.
endothermic reactions involve breaking of bonds. eg. boiling of water, where water molecules take in heat energy needed to break the bonds.

 

[AAnsarii]

qp33_w10_chem. 5(b)(iv) can i have d structure wid d bonds?

please sby ans dis i need 2 go 2 sleep..

 

[AAnsarii]

what does the square sign indicates in things like (CH2)2 -CH2-CH3
BREAKING BOND, FORMING BOND, BOND ENERGY AND WHAT IT HAVE TO DO WITH EXOTHERMIC AND ENDOTHERMIC

my unsolved questions remain unsolved, need help

square signs like what?

 

[Billy123]

Summer 2009 Chemistry Paper 32.
Can anyone teach me the Question Part B in Page number 7? Please help as soon as possible!

 

[Maz]

Nitrates nitrites... which metals give nitrates and which give nitrites quickly exam is tomorrow!

Sodium and potassium decompose when heated to their nitrites and oxygen.
lesser reactive metals decompose to form their oxides, nitrogen dioxide and oxygen.

 

[Ibrahim Basar]

Whats the formula for a nitrite?! and thanks dude

 

[imperial]

ok we talked about breaking bonds and forming bonds
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_w11_qp_33.pdf
check question 7 b(iii)

it talks about bond energy
help?

 

[imperial]

Whats the formula for a nitrite?! and thanks dude

NO2-1

the ion