POST YOUR BIO AND CHEM PAPER 1 DOUBT HERE !!!!

[fishcook]

YOu filter to remove the excess solid then concentrate the solution to get a saturated one then you filter to obtain crystals and heat to dry.
A solution means that both salts should be soluble since insoluble salts don't split up into ions.
Since silver chloride is insoluble,barium sulfate is insoluble so the only anion left is the nitrate..

never mind i got it.. sorry
thank you

 

[Skynox]

but dont silver chloride still contain chloride ions and same thing goes for barium ions in barium sulphate?

Yes but they don't split up into ions when in water/

 

[natsume hyuga]

so the reason its 10*2=20 and not 10/2= 5 because since there is less volume of water, there is more heat loss? I faintly remember this sorta concept being asked in a chemistry paper 6

ok for some reasoning in this .. first endothermic reactions dont show increase in temp so u eliminate all the answers with increase at the beginning .. u will have 2 choices now when one of the reactants is halved ( in this case the water fro 1000cm3 to 500cm3 ) then there will be a more decrease in temp shown this decrease will be double/twice that of the 1000 cm3 .. be careful only one of the reactants is changed the other remains constant .. therefore when the volume of water is halved the temp decrease is double (10 * 2 = 20 degrees decreased)

 

[Razo513]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s10_qp_13.pdf
Q20.. why is it D?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_qp_11.pdf
Q19.. why is it B?

i didnt quite understand Q20 .. BUT REGARDING Q19 Silver chloride is insoluble so if chloride ion were present it would precipitate. Similarly barium sulfate is insoluble. Only nitrates would be possible from the options given.

 

[Skynox]

One refers to the muscular wall and the other refers to it as a whole

 

[MERIHAN]

One refers to the muscular wall and the other refers to it as a whole

BUT HOW WILL WE KNOW !!! B/C THE LABELLING IS AT THE SAME POINT ?????

 

[L-Girl]

bio, question 15 november 2007 please

 

[Razo513]

so the reason its 10*2=20 and not 10/2= 5 because since there is less volume of water, there is more heat loss? I faintly remember this sorta concept being asked in a chemistry paper 6

yup u got it right .. no not 10/2 = 5 ... cuz logically for example if the rxn is exothermic if u have less reactants u will notice a higher temp change

 

[natsume hyuga]

WHY ARE THEY SAYING UTERUS AS A TISSUE IN ONE QUESTION AND ORGAN IN ANOTHER QUESTION ????? THANX IN ADVANCE View attachment 12079

look in the first one they are pointing to the lining of the uterus, which is made up of one kind of tissue, and the next they are pointing to the uterus basically, and the uterus is made up of many tissues so its an organ

 

[Skynox]

BUT HOW WILL WE KNOW !!! B/C THE LABELLING IS AT THE SAME POINT ?????

It is quite different one has like two layers and also in the other question he mentioned the name of the organ.

 

[Razo513]

BUT HOW WILL WE KNOW !!! B/C THE LABELLING IS AT THE SAME POINT ?????

in the first one they gave u 2 layers shown so obviously one is the uterus linning & the other layer is the uterus(oragn) itself .. in the second question they dont want to mix u up so they pointed to the uterus (organ) as a whole

 

[MERIHAN]

It is quite different one has like two layers and also in the other question he mentioned the name of the organ.

THANKS

 

[natsume hyuga]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s10_qp_13.pdf
Q20.. why is it D?
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_qp_11.pdf
Q19.. why is it B?

did u get the answer for the questions? Cuz i think skynox answered one of them

 

[MERIHAN]

in the first one they gave u 2 layers shown so obviously one is the uterus linning & the other layer is the uterus(oragn) itself .. in the second question they dont want to mix u up so they pointed to the uterus (organ) as a whole

THANKS

 

[saroooor]

whats the reasoning behind this?

Could you plz people clarify this to me ?? I am not able to understand it !!!

 

[Skynox]

Could you plz people clarify this to me ?? I am not able to understand it !!!

which one ?

 

[Razo513]

Could you plz people clarify this to me ?? I am not able to understand it !!!

let's say the opposite the the rxn is exothermic. when u half one of the reactants u will see that the temp rise is more noticable since the rxn takes place with fewer reactants same thing in endothermic rxn when one of the reactants is halved which is the water as shown from 1000cm3 to 500cm3 then there will be double (*2) the temp decrease

 

[saroooor]

The one for what happens if 5g of X is dissolved in 500cm3 of water .

 

[saroooor]

let's say the opposite the the rxn is exothermic. when u half one of the reactants u will see that the temp rise is more noticable since the rxn takes place with fewer reactants same thing in endothermic rxn when one of the reactants is halved which is the water as shown from 1000cm3 to 500cm3 then there will be double (*2) the temp decrease

Why isn't it half the temperature decrease like 5 instead of 10 ???!!!

 

[natsume hyuga]

Could you plz people clarify this to me ?? I am not able to understand it !!!

cancel the options with the increase in temp cuz clearly the question says its an endothermic reaction. ok now the concept behind this is that, because there is less volume of water, there is more temp loss. Why is that? I have no fricken idea!