Chemsitry Paper 31!!!!

[raiyanfarrukh]

i got 2.5 x 10^-3mol/dm^3.......

i don't know whose ryt over here but i don't understand why r u dividing 5/2 to get 2.5 there is one student in our school who did like u did!!

 

[Soldier313]

i don't know whose ryt over here but i don't understand why r u dividing 5/2 to get 2.5 there is one student in our school who did like u did!!

because ratio of 2I- : I2 is 2:1 and we were using iodide, not iodine for the experiment......so u have to divide by 2 because the question was asking about iodine i think......:/

 

[raiyanfarrukh]

i did that but i got 5*10^-4

 

[nerdybookworm]

no problem u will loose 1-2 marks for that but u will get the marks for the graph and for the table including units!!!!!

i hope so cz i did enter the units in the tavle and i took volume on x axis n rate on y axis i gota straight line too n the invigilator there sed dont copy even if yur ans are wrong they consider the method yuve done....according to tht u'll be rewarded..so i did it my way got almost the same but not exact..i hope there is ECF available..:/

 

[Soldier313]

i did that but i got 5*10^-4

um...for moles of thiosulphate i got 5 x 10^-5 and for moles of iodine i got 2.5 x 10^ -5and then concentration finally i got 2.5 x 10^-3.....wbu? what did u get for the moles part?

 

[raiyanfarrukh]

um...for moles of thiosulphate i got 5 x 10^-5 and for moles of iodine i got 2.5 x 10^ -5and then concentration finally i got 2.5 x 10^-3.....wbu? what did u get for the moles part?

Actually i don't remember that!! sorry

 

[Soldier313]

Actually i don't remember that!! sorry

owh okay no p

 

[Thampi4]

last calculation part on page 3 before the table i got 5*10^-4 mol/dm^3 as my conc for I2 what was urs??

Yes i got that exact value

 

[Soldier313]

Yes i got that exact value

owh man! i hope i didn't err somewhere then;((((

 

[melly713]

last calculation part on page 3 before the table i got 5*10^-4 mol/dm^3 as my conc for I2 what was urs??

i got d same ! wat u got for d othr 2 mole c ques?

 

[raiyanfarrukh]

i got d same ! wat u got for d othr 2 mole c ques?

which one u r talking about?

 

[Carty]

didn't the question say to divide by the total volume which was 20 cm3????? Then it would be 2.5*10-5* 1000/20 to give you 1.25*-3.... the question actually said divde by the total volume.. Didn't it?

 

[melly713]

Actually i don't remember that!! sorry

hey for final conc i got 4.9x10^-5 or -4 ..cant rem

 

[raiyanfarrukh]

hey for final conc i got 4.9x10^-5 or -4 ..cant rem

i got 5*10^-4

 

[raiyanfarrukh]

didn't the question say to divide by the total volume which was 20 cm3????? Then it would be 2.5*10-5* 1000/20 to give you 1.25*-3.... the question actually said divde by the total volume.. Didn't it?

i don't know about that total volume for that conc was 50cm^3 for which u had to find the conc!!

 

[Bumble bee]

Guys ..... wat if some1 makes a wrong observation and deduces their salt according to their own observation .... do they get the error carried forward mark ???

 

[raiyanfarrukh]

Guys ..... wat if some1 makes a wrong observation and deduces their salt according to their own observation .... do they get the error carried forward mark ???

maybe!!btw u shouldn't get any wrong observation unless u have used wrong reagents to identify!!

 

[Bumble bee]

maybe!!btw u shouldn't get any wrong observation unless u have used wrong reagents to identify!!

My reagents were correct .... jst that I had gone colour blind or something then .... .... Mixed up yellow nd cream ppt ... Sigh