Chemistry: Post your doubts here!

[pearl angel]

knowitall10 xhizors thanx alot

 

[knowitall10]

in j11 52 c we are trying to find the rate of rxn but we are not keeping the lid on the beaker. i dont understand that to take out rate of rxn accurately shouldnt we try to reduce heat loss by putting lid?
papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_52.pdf

Both, the marking scheme and the examiner's report say that no mark if sealed. So i u shouldnt place the lid. another point i noticed is tht the examiner's report said the the student confused the exp with standard enthalpy so that means that u only prevent heat loss in the enthalpy change questions.

 

[knowitall10]

knowitall10 xhizors thanx alot

No problem Any time!

 

[raamish]

in j12 51 2c) what is the reason for the anomalous pts and can u explain the equilibrating thing again

 

[xhizors]

in j11 52 c we are trying to find the rate of rxn but we are not keeping the lid on the beaker. i dont understand that to take out rate of rxn accurately shouldnt we try to reduce heat loss by putting lid?
papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_52.pdf

what is the relation between the rate and heat loss??
rate is the measure of time to complete the reaction and heat loss is heat loss..

 

[knowitall10]

in j12 51 2c) what is the reason for the anomalous pts and can u explain the equilibrating thing again

"Gas not equilibriated with increased temp" means that the volume was taken before the gas actually reaached equilibrium. in other words, the volume was recorded before 5 minutes were over. in the question, they place the syringe in increased temp for five mins, right? So at that temp, the student recrded the volume before five mins.

 

[Thampi4]

Hi
In p5
Question 1 when they ask u to give step by step description for planning an experiment and they give points to talk about, do we describe only those points?

Eg p5 o/n 12 q 1e

 

[raamish]

ok in n07 can u also explain the anomalous point at 7.5 time why did we write that the volume was measured too early and why did we not write that the point was below the line so the volume was recorded late. i want to know that when points are above the line do we assosciate them with x axis or y axis and the same for points below the line. This a very important question guys plzz answer it.

 

[knowitall10]

Hi
In p5
Question 1 when they ask u to give step by step description for planning an experiment and they give points to talk about, do we describe only those points?

Eg p5 o/n 12 q 1e

yea.. when the question says "give step by step discrip. by...." then you describe only those points, that'll be sufficient. but if the question says "give a step by step descrip. including...." then i recommend you describe the full procedure INCLUDING the points the question gave you.

 

[sagystu]

haha.. i don't think anything would happen, but i strongly recommend that you dont

thanks ,
i have a dear friend who packed it up with his stuff after the exam today , he didn't find out till he was home !!

 

[hela]

The reaction with iron(III) chloride solution AND PHENOL GROUP

 

[raamish]

hey can u guys answer my anomalous point question

 

[hela]

THE REACTION IRON3 CHLORIDE AND PHENOL

 

[knowitall10]

ok in n07 can u also explain the anomalous point at 7.5 time why did we write that the volume was measured too early and why did we not write that the point was below the line so the volume was recorded late. i want to know that when points are above the line do we assosciate them with x axis or y axis and the same for points below the line. This a very important question guys plzz answer it.

It depends on your line.. because when you get an anomalous on either side, they are never exactly the same dist away from the line. Look at my line below: The distance of A2 from the line is more than the distance of A1. So to describe the reason why A2 is anomalous, we'd talk about the y-axis. and to describe why A1 is anomalous, we'd talk about the x-axis. understand?

 

[TCHS]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s07_qp_5.pdf
QUESTION 2e)
When they say draw construction lines to derive etc they mean draw triangle & find gradient?? How will I do this question?

 

[raamish]

yeah sort of. i get the idea of it. But if im having problem giivng the reason of the anomalies plzz help me out thanks

 

[pearl angel]

It depends on your line.. because when you get an anomalous on either side, they are never exactly the same dist away from the line. Look at my line below: The distance of A2 from the line is more than the distance of A1. So to describe the reason why A2 is anomalous, we'd talk about the y-axis. and to describe why A1 is anomalous, we'd talk about the x-axis. understand? View attachment 25315

so is it always that the point which is further away from the line, we describe y-axis? what if there are 3 anomalies?

 

[raamish]

draw 2 lines instead of the triangle like one for x1 and y1 and another line for y2 and x2 and show the line to the intercept as well

 

[raamish]

but a2 is away from x axis too then why

 

[raamish]

ill give u an example in j12 51 i took the point above the line to the y axis and the pt below to the x axis. according to that the volume of the gas was coming greater so i wrote that the volume of the gas was attained when increasing temp. and if i wud have picked x axis then the vol. would be at lower temp so i would have wrote the correct statement. so what do i do to identify which axis to pick