A really hard chemistry question that keeps kinda repeating

[balloonsandhighlighters]

Alrighty its question 5b.
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s09_qp_3.pdf

Anyone know how to get the answer ?

The mark scheme says:

T3(PO4)2
Explain why 8cm3 react fully
Comment about mole ration


HUH?!

 

[ThatReallyReallyWeirdDude]

Alrighty its question 5b.
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s09_qp_3.pdf

Anyone know how to get the answer ?

The mark scheme says:

T3(PO4)2
Explain why 8cm3 react fully
Comment about mole ration


HUH?!

Ah yes
This question
Sorta hard to explain, I have it in m inbox somewhere when someone else asked me.
Here:
Okay
From the graph you can tell that 8cm^3 of Na3PO4 reacts with all 12 cm3 T's Nitrate
therefore the ratio of volumes of T Nitrate: Na3PO4 is 12:8
=3:2
Since the concentration is 1.00mole per decimeter , the volume ratio = mole ratio
Alternatively you could just see how many moles in 12cm3/8cm3 of each using no. of moles = conc. x volume but that just gives you 0.012:0.008 which simplifies to 3:2
So ratio of moles of T Nitrate: Na3PO4 is 3:2
That means 2 moles of sodium phosphate reacts with three moles of T nitrate.
THAT means the product of that reaction, the phosphate, has 2 moles of phosphate and three moles of T
So the formula is T3(PO4)2
I hope that makes sense!

 

[FATIMA1996]

ahhh that question i didnt know it at fist but now i do.
okay i'll try my best:
in the question it says 12 cm3 so "T" IS 12.
from the graph after 8 cm3 the the graph is constant so "P" is 8. so now divide both of them with 4 so the answer is
T3(P04)2

 

[svenas]

Ah yes
This question
Sorta hard to explain, I have it in m inbox somewhere when someone else asked me.
Here:
Okay
From the graph you can tell that 8cm^3 of Na3PO4 reacts with all 12 cm3 T's Nitrate
therefore the ratio of volumes of T Nitrate: Na3PO4 is 12:8
=3:2
Since the concentration is 1.00mole per decimeter , the volume ratio = mole ratio
Alternatively you could just see how many moles in 12cm3/8cm3 of each using no. of moles = conc. x volume but that just gives you 0.012:0.008 which simplifies to 3:2
So ratio of moles of T Nitrate: Na3PO4 is 3:2
That means 2 moles of sodium phosphate reacts with three moles of T nitrate.
THAT means the product of that reaction, the phosphate, has 2 moles of phosphate and three moles of T
So the formula is T3(PO4)2
I hope that makes sense!

plz plz I need ur help in this question:
draw structural formula of a man-made polymer with amide linkage (protein ) plz draw for me bonds also....needed urgently

 

[svenas]

Ah yes
This question
Sorta hard to explain, I have it in m inbox somewhere when someone else asked me.
Here:
Okay
From the graph you can tell that 8cm^3 of Na3PO4 reacts with all 12 cm3 T's Nitrate
therefore the ratio of volumes of T Nitrate: Na3PO4 is 12:8
=3:2
Since the concentration is 1.00mole per decimeter , the volume ratio = mole ratio
Alternatively you could just see how many moles in 12cm3/8cm3 of each using no. of moles = conc. x volume but that just gives you 0.012:0.008 which simplifies to 3:2
So ratio of moles of T Nitrate: Na3PO4 is 3:2
That means 2 moles of sodium phosphate reacts with three moles of T nitrate.
THAT means the product of that reaction, the phosphate, has 2 moles of phosphate and three moles of T
So the formula is T3(PO4)2
I hope that makes sense!

sorry not man made but natural (protein) sorry

 

[ThatReallyReallyWeirdDude]

sorry not man made but natural (protein) sorry

plz plz I need ur help in this question:
draw structural formula of a man-made polymer with amide linkage (protein ) plz draw for me bonds also....needed urgently

Instead of -CHR- You can put boxes I think
But has to be different boxes, and at least 3 I think:

 

[ThatReallyReallyWeirdDude]

Also, man made would be the same except instead of having CONH CONH it would be CONH NHCO CONH NHCO, and would only have two different boxes

----------CO-|Box|-CO-NH-|Box|-NH----------

 

[balloonsandhighlighters]

Ah yes
This question
Sorta hard to explain, I have it in m inbox somewhere when someone else asked me.
Here:
Okay
From the graph you can tell that 8cm^3 of Na3PO4 reacts with all 12 cm3 T's Nitrate
therefore the ratio of volumes of T Nitrate: Na3PO4 is 12:8
=3:2
Since the concentration is 1.00mole per decimeter , the volume ratio = mole ratio
Alternatively you could just see how many moles in 12cm3/8cm3 of each using no. of moles = conc. x volume but that just gives you 0.012:0.008 which simplifies to 3:2
So ratio of moles of T Nitrate: Na3PO4 is 3:2
That means 2 moles of sodium phosphate reacts with three moles of T nitrate.
THAT means the product of that reaction, the phosphate, has 2 moles of phosphate and three moles of T
So the formula is T3(PO4)2
I hope that makes sense!

OH MY GOD IT DOES MAKE SENSE THANK YOUUUU SOO MUCH!!

 

[svenas]

Also, man made would be the same except instead of having CONH CONH it would be CONH NHCO CONH NHCO, and would only have two different boxes

----------CO-|Box|-CO-NH-|Box|-NH----------

thanks man ..wish u all the best in chemistry ...
Also for the question u explained lately about the height of ppt...I understood but u said volume ratio=mole ratio when mole is in dm3 or when both have same concn or when both have same concn and is 1?? which one of these will mole ratio be equal to volume ratio??

 

[ThatReallyReallyWeirdDude]

OH MY GOD IT DOES MAKE SENSE THANK YOUUUU SOO MUCH!!

Aww you're welcome!
I remember first time I answered it, I got to the ratio of TNO3:Na3PO4=3:2, and then I tried to make an equasion and balance it using that ratio ^^ I got the right answer but sorta impossible to explain.
Hope I helped!

 

[ThatReallyReallyWeirdDude]

thanks man ..wish u all the best in chemistry ...
Also for the question u explained lately about the height of ppt...I understood but u said volume ratio=mole ratio when mole is in dm3 or when both have same concn or when both have same concn and is 1?? which one of these will mole ratio be equal to volume ratio??

Mole ratio is only equal to volume ratio when the two solutions have the same concentration.
Example: 0.5mol/dm3 solutions of NaOH and HCl
NaOH + HCl->NaCl + H2O
The mole ratio is 1:1
Using formula No. of moles = Concentration x Volume, since we know no. of moles and concentration we can find the volume of solutions required o have 1 mole.
So vol = no. of moles / concentration = 1/0.5 = 2 dm3 which is true for both solutions.
So 2dm3 of NaOH reacts with 2 dm3 of HCl - so volume ratio is 2:2 = 1:1 = mole ratio.
It's not very important You can just find the number of moles in the volumes and then use mole ratio