Biology; Chemistry; Physics: Post your doubts here!

[Dark Destination]

haha i wrote carbon oxygen double bonds. cuz there wer c=o bonds. no c=c bonds i culd see

yes, exactly. Thats why i wrote nothing related to atoms.
I didn't specify.
I thought their would be one mark for DOUBLE BONDS.. and one mark for MANY or IN A NUMBER OF PLACES, as that is what POLY means.

But now people are saying their was a mark for saying Double bonds BETWEEN CARBON ATOMS

 

[M.Omar]

So the marking scheme did have one mark allocated for saying C-C?

I looked through year 11 to 13, can't find it :/

http://papers.xtremepapers.com/CIE/...O Level/Chemistry (5070)/5070_s11_qp_22.pdfit was the second ppr I looked into...

 

[Skhan94]

yes the endo one.... in which Fe2O3 was there?
are you sure?

 

[Lilly2318]

yes the endo one.... in which Fe2O3 was there?
are you sure?

yes in part one if temp incrses forward reaction incrss
in second part if pressure incrss , backward reaction incrss

 

[Dark Destination]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s11_qp_22.pdfit was the second ppr I looked into...

When i did this paper at home, i wrote C-C double bonds.
But in the paper we had, their was a fat shown, and they said it was polyunsaturated. And it had Double bonds between C and O, like C=O.
No C=C.

That made me think it might not always be between C=C.

 

[Skhan94]

yes in part one if temp incrses forward reaction incrss
in second part if pressure incrss , backward reaction incrss

No! the first one you did right but in the second one if the pressure increases the rate of forward will increase
cause there were 7 moles on the reactant side and 4 on the product so equilibrium is shifted to product side!

 

[M.Omar]

When i did this paper at home, i wrote C-C double bonds.
But in the paper we had, their was a fat shown, and they said it was polyunsaturated. And it had Double bonds between C and O, like C=O.
No C=C.

That made me think it might not always be between C=C.

I absolutely agree..Look I am not saying urs is wrong..not by a long shot..I am just saying its wht they wrote in MS tht,s all...Like I said they do amend the questions and perhaps at higher levels unsaturation may refer to other double bonds but in Olevels they just want us to get the gist or like tht and hence they will,in this case, consider other perfectly accurate ans as well

 

[M.Omar]

No! the first one you did right but in the second one if the pressure increases the rate of forward will increase
cause there were 7 moles on the reactant side and 4 on the product so equilibrium is shifted to product side!

Dude,hate to break it to u,the quation read
3Fe +4H20(g)=Fe203 and 4H2(g)
since pressure affects only gaseous reaction the 4 moles of each gas steam and water r present and hence any pressure chng will not shift the equilibrium

 

[Lilly2318]

No! the first one you did right but in the second one if the pressure increases the rate of forward will increase
cause there were 7 moles on the reactant side and 4 on the product so equilibrium is shifted to product side!

pressure ONLY acts on GASES so it wud only act on stem and frm other side on H2

 

[Dark Destination]

I absolutely agree..Look I am not saying urs is wrong..not by a long shot..I am just saying its wht they wrote in MS tht,s all...Like I said they do amend the questions and perhaps at higher levels unsaturation may refer to other double bonds but in Olevels they just want us to get the gist or like tht and hence they will,in this case, consider other perfectly accurate ans as well

That's just unfair. They gave a diagram of an unsaturated fat, that clearly showed it was not necessarily between carbon carbon atoms.
Even Carboxylic acids are unsaturated, and can decolourize bromine. They have a double bond. And something that has a lot of Double bonds, is polyunsaturated.
I don't understand their mark allocation of having one mark for saying ''Carbon carbon'' :/
So i lose a mark for not ''memorizing'' the marking scheme.

 

[FLRNAB]

I assume u want me to state tht it can be any one or tht I am not sure which one...The pt I am trying to say is tht despite the refraction(which is one time only)it will meet at tht point and we can easily adjust the line accordingly

http://www.physicsclassroom.com/class/refrn/Lesson-5/Image-Formation-Revisited
U might want to rephrase tht.. I think i cant convey it properly enough ..Hook up the conv lens img formation.U will get wht I mean

I know that -_-
You aren't getting what I am telling you. I am not saying it's not possible. I am saying you need refractive index and angle of incidence to correctly draw the path of a ray.

 

[Skhan94]

but isn't this rule applied to the equation if its totally related to gases?

 

[Lilly2318]

but isn't this rule applied to the equation if its totally related to gases?

nope. Pressure only acts on gases whwerever they r

 

[M.Omar]

I know that -_-
You aren't getting what I am telling you. I am not saying it's not possible. I am saying you need refractive index and angle of incidence to correctly draw the path of a ray.

Yar ...we get the first point of contact by passing ray undeviated thru the cdntre...We now get out first point..NOW all the rays frm tht point will converge at tht point which they illustrated in tht site....So it does not matter whether we know abt refr index or not...I don't want or like to repeat but it does not matter here abt refr index and u r saying tht a parallel line from tht point is the only corr answer...No it is not and not on ur pretext tht it passes thru the focal point....Let me be clarified as well do u also mean to tell me tht the points where the rays meet is the focal length of the lens?(from the lens to pts they converge)just as a check..
Well, the rest I have simply been restating to u before

 

[FLRNAB]

Yar ...we get the first point of contact by passing ray undeviated thru the cdntre...We now get out first point..NOW all the rays frm tht point will converge at tht point which they illustrated in tht site....So it does not matter whether we know abt refr index or not...I don't want or like to repeat but it does not matter here abt refr index and u r saying tht a parallel line from tht point is the only corr answer...No it is not and not on ur pretext tht it passes thru the focal point....Let me be clarified as well do u also mean to tell me tht the points where the rays meet is the focal length of the lens?(from the lens to pts they converge)just as a check..
Well, the rest I have simply been restating to u before

When did I say only parallel line is correct answer? Any CORRECT ray is an answer provided that it is correct.
Yeah focal point.

 

[M.Omar]

When did I say only parallel line is correct answer? Any CORRECT ray is an answer provided that it is correct.
Yeah focal point.

so thts the fountainhead of ur misconception yar points do not always converge at focal point..Infact they rarely converge at f infact in practicals they converge very close coz theoretically tht,s not completely possible..It,s not the focal point...check the site does the image form at focal pt?

 

[Lilly2318]

so thts the fountainhead of ur misconception yar points do not always converge at focal point..Infact they rarely converge at f infact in practicals they converge very close coz theoretically tht,s not completely possible..It,s not the focal point...check the site does the image form at focal pt?

u ppl still fighting on physics. forget it. relax. whats next ppr u ppl hv?

 

[FLRNAB]

so thts the fountainhead of ur misconception yar points do not always converge at focal point..Infact they rarely converge at f infact in practicals they converge very close coz theoretically tht,s not completely possible..It,s not the focal point...check the site does the image form at focal pt?

The question said that it was at focal length where the image formed. My diagram was relating to that. I know it wont be at focal point unless stated But all rays do pass through focal point except the ones passing through the center. Here your site showing how to draw ray diagrams. the original drawing was not drawn like the way shown.

 

[Skhan94]

anyone on snapchat?

 

[FLRNAB]

u ppl still fighting on physics. forget it. relax. whats next ppr u ppl hv?

NO