how was chem. p5

[CaptainDanger]

No paper discussion within 24 hours. Come back tomorrow to see your posts.

 

[CaptainDanger]

You can discuss now.

 

[angelicsuccubus]

hey.....how would you collect water using liebeg condesor...wont it fall back in the boiling tube.....it was written how it will be collected.......

you know .. I just thought of using a condensing tube with ice in it.. cause its done in a school lab plus they gave us ice to use.. (and Ive never heard of liebeg condensor until now)

 

[angelicsuccubus]

well u i think we must have drawn ice bath that is abeak filled with crushed ice.....and A U TUBE is there.....immersed in crushed ice ....where water will get cndensed and ccollected..........cos wid liebig condenser ....wehere u ll put the ice.....cos liebig cndenser works by a jacket of cold water not CRUSHED Ice.........
pm me the anser to last part u ppl wrote

ooh that's what I did... I thought of a u-tube coming into a beaker with ice.. and the top horizontal part of the tube continuing in to the syringe for N2O... but then I hadn't studied at all for this paper so *shrug*

 

[hassam]

yea jux one problemmmm........i dint ensure gas was collected at 25 degree celsius

 

[hassam]

well did u guyx ensure gas was collected at 25 degree celsius???

 

[Aahliya]

Guys how did u plot the graph.. I mean did u take pressure on y-axis and Volume on x-axis or vice versa ??

 

[MahirLatif]

those who mentioned a leibig condenser are wrong. The very first part of the question mentions apparatus EASILY available in a school lab. Plus a condenser can't be attached simply anywhere, and it uses water, not ice. The Gradient was 2.7 x 10^-4 for the second question. ( although i wrote 3 x 10^-4 , depends on how accurately you took the intial slope)..

 

[MahirLatif]

The Last graph was a straight line which went on to curve at higher pressure.
The answers to the very last three questions.
Why graph unsuitable to confirm Boyle's Law ? because gradient is not constant.
Why take initial slope ? because the graph curves at higher pressures and gradient again, wont be constant
significance of my above answer ? PV= Constant at lower pressures... then it changes .. means the gas being tested behaves as an ideal gas at lower Pressures only

hope that helps. Feel free to correct me if anyone thinks I wrote wrong

 

[MahirLatif]

Guys how did u plot the graph.. I mean did u take pressure on y-axis and Volume on x-axis or vice versa ??

Pressure on X axis. 1/Volume on Y axis

 

[Goodfella]

well did u guyx ensure gas was collected at 25 degree celsius???

No, and many of the good students in my center didn't

 

[Goodfella]

those who mentioned a leibig condenser are wrong. The very first part of the question mentions apparatus EASILY available in a school lab. Plus a condenser can't be attached simply anywhere, and it uses water, not ice. The Gradient was 2.7 x 10^-4 for the second question. ( although i wrote 3 x 10^-4 , depends on how accurately you took the intial slope)..

then how did u condense the water bro? :O

 

[hassam]

Pressure on X axis. 1/Volume on Y axis

well did u ensure gas collected at 25 degrees....cos many students like me dint do that....nd was it necessary

 

[princesskt]

well did u ensure gas collected at 25 degrees....cos many students like me dint do that....nd was it necessary

I THINK IT WAS NOT NECESSORY BECAUSE THE GAS SYRING WE SHOWED WAS AUTOMATICALLY AT RTP BECAUSE IT WAS NOT HEATED.......WE CAN NOT PLACE IT IN A WATER BATH AS WELLLLLLLL.................

 

[MahirLatif]

well did u ensure gas collected at 25 degrees....cos many students like me dint do that....nd was it necessary

No i did not. but i dont think it was necessary, as the gas syringe was already at room temp. and how were you supposed to control the temperature of the gas in the syringe anyway ? can't place it in a water bath can you.. ?

 

[hassam]

yea ....no....i also dint ......

 

[jackrabbit]

The Last graph was a straight line which went on to curve at higher pressure.
The answers to the very last three questions.
Why graph unsuitable to confirm Boyle's Law ? because gradient is not constant.
Why take initial slope ? because the graph curves at higher pressures and gradient again, wont be constant
significance of my above answer ? PV= Constant at lower pressures... then it changes .. means the gas being tested behaves as an ideal gas at lower Pressures only

hope that helps. Feel free to correct me if anyone thinks I wrote wrong​

The Question clearly states, draw a curve OR line of best fit, so a line which extends into a curve, or a straight line throughout which passes through the origin could both have been correctly drawn.

The question asked IF the graph was suitable to confirm Boyle's Law, and if you drew a straight line, which passes through the origin, then obviously the answer would be yes. I dont know if you can say it was completely unsuitable, after all, there was a region in the beginning where the gradient was constant :/

Yes, you take the intial slope because if a curve was drawn, the gradient would not be constant at higher pressures, alternatively had you drawn a straight line, you could say the a gas deviates from ideality at high pressures, which would mean the equation would not be valid.

The significance of the gradient was that it was the inverse of the constant in PV= constant.

 

[leadingguy]

Guys how did u plot the graph.. I mean did u take pressure on y-axis and Volume on x-axis or vice versa ??

fr second big graph I took 1/volume on y axis

 

[MahirLatif]

then how did u condense the water bro? :O

Well I can be perfectly wrong too, but I diverted the mixture of gases to a flask placed in an ice bath (beaker/bucket full of ice) which was at 0 degrees. The vapours condensed there and I collected the water in the flask. the other Gas just passed on to the syringe i attached to the flask.

My apparatus was basically this :
Corked flask with one tube going out.. (where i heated the solid)
continue to tube going in second corked flask's BOTTOM.. this was the flask placed on ice.
second tube at mouth of second flask going into a syringe.

 

[MahirLatif]

The question asked IF the graph was suitable to confirm Boyle's Law, and if you drew a straight line, which passes through the origin, then obviously the answer would be yes. I dont know if you can say it was completely unsuitable, after all, there was a region in the beginning where the gradient was constant :/

did u read the question ? they were asking about the graph that was GIVEN .. not the one we drew. and that was a curve and hence completely unsuitable