confirm salts chem34

[obr***]

In the last part, I wrote SYSTEMATIC error! And i have a confusion! Were we supposed to take the errors as 1.0/12*100 and 0.1/5.6*100 or we should have halved the least graduation????

no u r ryt we had to do it by this method w/o halving

 

[Buffer Solution]

oh no i wwrote 84 instead of 30 in place of m...shit

 

[Akshay]

common cation was NH4 ..mine did turn brown ..therefore its Fe 2+ no doubt..truly

 

[Syed.Mazahir.Rizvi]

yup i got the common as NH4 and Fe2+

 

[Deceit1991]

i got Cr :S

 

[tiralolx]

the second cation is Fe2+ rightt?? i wrote Cr3+but then i changed it in the last minute. >.<

did fb9 showed any reaction with K2Cr2O7?? some of my friends' did change to green but mostly it had no reaction.

i think i messed up the calculation part. i didn't have any idea how to calculate it. but at least i didn't leave it blank
just do watever i can

 

[tiralolx]

hey thr was another trick question .. when theyd asked for error in single thermometer reading it was 0.5 *C ... but then they asked percentage error for the CHANGE in temperature of -12*C ..
as change is found by a - b sth ... the error would be 0.5 + 0.5 = 1 . i solved it this way .. got 8.3 % error .

maybe i just overthought it all .. howd u guys do it ?

i did the same way too>.<
for the single balance reading, is it 0.05??

 

[ashhadazam]

Dont know abt that part but my K2cr207 was wonderfull.. turnd green instantly

 

[ashhadazam]

I got enthalpy change 25.56... gradient 2.36 !!!
And i think u had to define the error.. IT was parallex error.. because in parallex error u take both the readings different so the net difference actually gets u the correct reading !!!

 

[ashhadazam]

Guyz we dint had to se OUR uncertainties.... It was given in the question that the least measrement was 0.1 for mass and 1 for temperatre !!

 

[el_nino9]

Uncertainaties are usually the half of the least value. yep the common ion was NH4+, Fe2+ was the other cation. with sulfate being present in FA 7. The gradient was 2.3 and the final answer was 24.9 kJ/mol. FA 9 was ketone and FA 10 and 11 were alcohols.

I wrote systematic error. Dont know if thats wrong. what were the suggestions that u guys made to improve the exp in ques 1?

 

[KhajistaNizam]

yeah el nino
i gt da same values az urs!!!!

n im abit confusd abt da error ques too!!!
bt i wrote dat da initial temp of both stdnts r diffrnt although both r duing da prac at da same time so da temp shud b same!!!!
argh!!!
cudnt fink of nefing else!!!

 

[ashhadazam]

Parallex error only stating !

 

[apple]

The error was systematic error. There was a problem with both the thermometers that 'cause all the readings to deviate by a certain amount. That's why they had the same answers but different reading.s

 

[ashhadazam]

well they were using the same thermometers i think !!! The readings had a differnce of -1 in both initial and final... this could only happen if the person takes the reading wrongly.. Systematic error is a bigger classigfication.. Parallex error also comes under systematic erro !

 

[apple]

well they were using the same thermometers i think !!! The readings had a differnce of -1 in both initial and final... this could only happen if the person takes the reading wrongly.. Systematic error is a bigger classigfication.. Parallex error also comes under systematic erro !

No, parallax error is human error. Systematic error is error with the instruments. It didn't say anywhere that they were using the same thermometer.

 

[ashhadazam]

Um well .. Correction : Parallex error IS a systematic error !! Anyways it was a one mark question.. if u wrote systematic , u could mean a lot of things.. paralex condensed it.. but still.. CHeers ! :mrgreen:

 

[ashhadazam]

and there was no problem IN the termometers.. there was a problem in taking the reading. !! room temperature cant be diff for 2 ppl :O

 

[hafsahnaim]

Y is parallax error a systematic error? It's not caused by faulty instruments! I wrote random error... under which I think, parallel error comes, because it depends on the care of the experimenter.

 

[ashhadazam]

Well the difference between systematic and random is that random means scattered.. some values ae below and some are above.. file in systeamtic they folow a continuous patternm like in zero error !!