HOW WAS CHEM PAPER 5?

[samy]

wel lukx lyk i did da calculation wrng.....
Cn sumbdy plx tel abt da exp as the wordx 'temp range ' cnfuxd a lil!

temperature range means the different temperatures at which you will conduct the experiment... eg 20*C to 80*C

hmmmm okay...did sumthin lyk dat ..but still tend to loose marks

 

[SilentAssassin]

we are asked to draw "best fit line"/ so it is imposible to draw best fit curve ?

A line does not necessarily mean a straight line... a curve is a line as well... most of my friends and I got into an argument regarding this too... but I think it's alright to get a curve...

A line of best fit is a line that best approximates pieces of data.
A curve of best fit does the same thing, except that it is a curve.

The use of each one will depend on how the data behaves. If the data tend to follow a line, then a line of best fit will be used. If, however, they seem to follow a curve, for example, then you would use a curve of best fit.

This was exactly what I had in mind when drawing the graph... I mean most of the points fit quite well in a curve.... With just two anomalies... A straight line was causing too many points being left out... But it really doesn't matter too much... There will be a loss of a maximum of one mark for the incorrect shape of graph... The marks that follow will be ECF... and GT will be low... No worries... Best of luck with Paper 4 everyone! The Big One...

 

[honeycoveredcookie]

Well.
It was a LINE, not a curve because they clearly mentioned a "line of best fit."
There were a lot of anomalies, and that's normal. My line went through just 4 points.
It was endothermic for sure.
I think using a bunsen burner to regulate the temperature is wrong for the first question. Its a water bath so that you can regulate the temperature.

 

[AayushR]

2 points!

 

[xarak]

can sumbudy plz rite the plannin part of the first question.thnx

 

[Fauziya]

wich varient did u guyz had??
i gave ppr51 2dy...

 

[WellWIshER]

i gave 51 as well

 

[Fauziya]

i found it fyn,,bttr thn the past pprz..

 

[osamatarar8842]

q1 was good,q-2 graph was a bit deluding,however it was better than wt i was expecting.

 

[Fauziya]

q1 was the rate of decomposition of Group 2 carbonates....n q2 was to check the molra ratio of NaNO3 n NaNO2...

 

[AN10]

i messed the whole of que 1..a bit of que 2 aswell...i did not write that we had to heat both the reactants separately..messed everything..misunderstood the range of temp..and.....very bad ..very tensed.

i messed up the experiment too...didn't heat the reactants separately and so the procedure and temperature measurements r wrong
i hope the thresholds r low n ppr 4 goes well!

 

[ima_shah2002]

the papers wasnt that bad... btw in the second question for the anomalous values did u get one at 90 and another at 45.. wat could have been the reasons... for the one at 90 the solubility was higher than supposed to be -- crystals not seen in this much amt of volume/redissolved.. and the one at 45... some water may have evap and so lower soluiblity observed...waddya think dunno....

 

[cool]

i messed the whole of que 1..a bit of que 2 aswell...i did not write that we had to heat both the reactants separately..messed everything..misunderstood the range of temp..and.....very bad ..very tensed.

i messed up the experiment too...didn't heat the reactants separately and so the procedure and temperature measurements r wrong
i hope the thresholds r low n ppr 4 goes well!

yah same hopes i have..but rite now i feel like crying ...y did i mess up ...if i had thought a little bit before writing the experiment and drawing tha apparatus, i could have done much better.but it was too late wen i realized. ..i can't get this off my head..Allah kare khair ho jaye...P4 is too difficult aswell..kia karun boht tension ha

 

[SilentAssassin]

May be this will clear everyone's doubts... regarding the shape of the graph... Potassium Chlorate (V) is KClO3... just check these two pages out:

http://www.google.com/imgres?imgurl=htt ... rQenpbzCCg

http://www.google.com/imgres?imgurl=htt ... rQenpbzCCg

 

[Fauziya]

i messed the whole of que 1..a bit of que 2 aswell...i did not write that we had to heat both the reactants separately..messed everything..misunderstood the range of temp..and.....very bad ..very tensed.

i messed up the experiment too...didn't heat the reactants separately and so the procedure and temperature measurements r wrong
i hope the thresholds r low n ppr 4 goes well!

yah same hopes i have..but rite now i feel like crying ...y did i mess up ...if i had thought a little bit before writing the experiment and drawing tha apparatus, i could have done much better.but it was too late wen i realized. ..i can't get this off my head..Allah kare khair ho jaye...P4 is too difficult aswell..kia karun boht tension ha

ab afsos na karen..ppr4 hai..uski acche se tayari kijiye...inshaALLAH sab sahi ho jayega..ALLAH(swt) pe bharosa rakhiye...ab ppr5 ka soch ke agla ppr mat kharab kijiye...bhool jaiye..head for the nxt...with a +ve head..

 

[aquariangurl]

OMG! You guys..I thought P5 was so good..I can't find a single place where I'm actually losing marks, though my P2 was W.E.I.R.D, but P5 went really good for me =/

 

[ima_shah2002]

OMG! You guys..I thought P5 was so good..I can't find a single place where I'm actually losing marks, though my P2 was W.E.I.R.D, but P5 went really good for me =/

Since ur ppr went good tell me at what temo did u get anomalous values?? and what wr ur reasons

 

[aquariangurl]

I took the value at 85'C because the mass taken was higher than the rest, ie all the other masses were below 0.10 but this one was 0.14
Then I took values at 45'C (I think), 60'C & 70'C because they even after having high temperatures were lying below the line of best fit, becauze the normal trend would be that as temperature increases solubility increases, but at these temperatures, solubility was decreasing.
It's right becauze I checked it with my teacher

 

[maniac33]

me too.... got 2 anamolus points..but both on the same side of the line ... :%)

 

[ohwellOK]

Alright trolls, here's best fit linessssss.
http://www.google.com.my/search?hl=en&b ... a=N&tab=wi