Physics, Chemistry and Biology: Post your doubts here!

[shingiechingz@8]

guys paper was easy hopefully will get 70 above in p3 just because of my silly mistake and p1 is like wow!!!!
i am happy today too much because chemistry is over

awesome right?

 

[sj0007]

I put the native element the last. The one that reacted with cold water the highest. What did you put?

Same, cuz like they told us to write the most reactive first!

 

[shingiechingz@8]

What was that reversible reaction of Copper chloride of blue and pink in paper 11? I know it turns back to pink, but does temperature increase or decrease in the reverse reaction?

i wrote that it decreases as it released steam when heated which turned it from pink to blue

 

[sj0007]

What was that reversible reaction of Copper chloride of blue and pink in paper 11? I know it turns back to pink, but does temperature increase or decrease in the reverse reaction?

Yessss!
Even I was confused at first but I put it as decrease cuz it was an exothermic reaction................ wbu?

 

[shingiechingz@8]

Same, cuz like they told us to write the most reactive first!

mee too

 

[sj0007]

mee too

Yay!

 

[shingiechingz@8]

what abut the question of the wood vs carbon what was it?

 

[sj0007]

what abut the question of the wood vs carbon what was it?

I wrote that wood may have a low carbon content producing less carbondioxode (I am probably going to lose a mark or two in this ques)
U?

 

[masterex567]

Yessss!
Even I was confused at first but I put it as decrease cuz it was an exothermic reaction................ wbu?

I put that at first too, then changed it to increase. I was confused whether they're asking for temperature of the products or temperature right after mixing.

 

[sj0007]

I put that at first too, then changed it to increase. I was confused whether they're asking for temperature of the products or temperature right after mixing.

What did u do in the wood thingy?

 

[Saad the Paki]

I put that at first too, then changed it to increase. I was confused whether they're asking for temperature of the products or temperature right after mixing.

I wrote increase too cuz i think a similar question has come in a previous paper
And anyways the back reaction is exothermic so i supppse temp has to increase

 

[Saad the Paki]

What did u do in the wood thingy?

I wrote that tress take in CO2 from atmosphere during photosynthesis so when it is burnt the carbon dioxide formed replaces the carbon dioxide taken in thus there is no extra CO2

 

[shingiechingz@8]

what about the question on diffusion (last one). What was the position of the letter?

 

[Saad the Paki]

So in a sound wave...
A compression is a region of high pressure and rarefaction a region of low pressure?
Or is it the other way round?

 

[Saad the Paki]

what about the question on diffusion (last one). What was the position of the letter?

C cuz ethylamine has lower mass so it will difuse fasster

 

[Ahmed Elsiddig]

I wrote it was A because the long one diffuses less and hbr diffuses more

 

[shingiechingz@8]

C cuz ethylamine has lower mass so it will difuse fasster

not HBr right?

 

[sj0007]

So in a sound wave...
A compression is a region of high pressure and rarefaction a region of low pressure?
Or is it the other way round?

U are correct

 

[sj0007]

not HBr right?

Yes, HBr had a molecular mass of like 81
So it diffuses relatively lesser

 

[shingiechingz@8]

what was the relative molecular mass of ethylamine vs HBr?