How was Chemistry P34?

[shafayat]

yeah yeah !! first I wasn't ! but then after thinking over it I am sure its correct !!

yeah man i wrote that too..... and are you sure about the ethanol ethanal and ethanoic acid one ???

 

[shafayat]

fb5 was naoh ​

fb6 feso4​

fb7 mixture of znNo3 and KI​

fb8 was lead nitrate​

fb9 was na2so4​

cnfirmed frm a supervisor​

man NaOH was correct for me !!
then I thought fb7 cudnt be zinc iodide cuz the name sounded too awkward
so I wrote lead iodide ! ALTHOUGH I HAD WRITTEN CORRECT AT FIRST :/
I just hate my instincts :? :/ :/
fb9 we only needed to find so4 or so3

 

[hamzadar2006]

I got the titre volume 22.5 but our teacher got 23 so how many marks would i lose?
BTW i got 22.5 thrice consecutively

 

[talha196]

man NaOH was correct for me !!
then I thought fb7 cudnt be zinc iodide cuz the name sounded too awkward
so I wrote lead iodide ! ALTHOUGH I HAD WRITTEN CORRECT AT FIRST :/
I just hate my instincts :? :/ :/
fb9 we only needed to find so4 or so3

man i cudnt even conclude name of one salt frm the tests we did..... so i carried out seperate tests for zinc, lead and iodide myself with naoh agno3 and ammonia but still got sulfate wrong :/

 

[talha196]

I got the titre volume 22.5 but our teacher got 23 so how many marks would i lose?
BTW i got 22.5 thrice consecutively

dont worry man i think a difference of +-2 is acceptable my supervisor reading was 21 i got 20.9 as rough(rough titration must be greater thn the final value) and i got 20.7 twice and 20.6 as the last one..... so ticked the 20.7 and used it in further calculations

 

[Nightmare***]

hey for the last question....i chose tollens reagent nd NaCO3....am i right ????

 

[talha196]

hey for the last question....i chose tollens reagent nd NaCO3....am i right ????

nahco3 dude

 

[hamzadar2006]

hey for the last question....i chose tollens reagent nd NaCO3....am i right ????

Yeap u r right

 

[hamzadar2006]

dont worry man i think a difference of +-2 is acceptable my supervisor reading was 21 i got 20.9 as rough(rough titration must be greater thn the final value) and i got 20.7 twice and 20.6 as the last one..... so ticked the 20.7 and used it in further calculations

rough titration had to be greater? i never knew that .

 

[Usman04]

CAN ANYONE TELL ME WHICH ANION IS PRESENT IN FB9 SULPHAATE OR SULPHITE

 

[Dukeofwin]

CAN ANYONE TELL ME WHICH ANION IS PRESENT IN FB9 SULPHAATE OR SULPHITE

SULFATE

 

[shafayat]

I got the titre volume 22.5 but our teacher got 23 so how many marks would i lose?
BTW i got 22.5 thrice consecutively

cant say depends on how examiners mark ! but usually -1 for every .1 difference from your invigilator ! ok ?
there fore three mark from accuracy .. probably

 

[shafayat]

dont worry man i think a difference of +-2 is acceptable my supervisor reading was 21 i got 20.9 as rough(rough titration must be greater thn the final value) and i got 20.7 twice and 20.6 as the last one..... so ticked the 20.7 and used it in further calculations

not +- 2 its +- 0.2

 

[shafayat]

rough titration had to be greater? i never knew that .

neither did I but its kindof common sense ! you do rough to judge the amount needed ! so you just do hectically but when doing trials ! we do point by point therefore more accurate

 

[saadgujjar]

in q1 we have to use T1 for all readings to find change in temperature or first find initial temperature

 

[saadgujjar]

Plz explain

in q1 we have to use T1 for all readings to find change in temperature or first find initial temperature

 

[-rimsa]

nahco3 dude

Care to elaborate?

 

[shafayat]

in q1 we have to use T1 for all readings to find change in temperature or first find initial temperature

well the question said to use t1 only ! but I kept on taking initial temperature ! cuz my room temp kept changing !

 

[shafayat]

Care to elaborate?

eh ? no need for NaHCO3 ! NaCO3 is fine ! cuz it only reacts with acid !

 

[Chucky]

I got the titre volume 22.5 but our teacher got 23 so how many marks would i lose?
BTW i got 22.5 thrice consecutively

Relax.
They don't mark strictly on your values. Only on the steps you took to find the answers and how you performed the experiment (if you did it according to instructions or not).
Or else, we'd all get C's for getting different titre values.