POST ALL CHEMISTRY QUESTIONS HERE

[Silent Hunter]

correct

 

[Maleeha]

so sulfuric acid doesn't make any difference??? cuz it also ionizes to give H+ ion?

 

[abcde]

^Yes!

 

[thewantedguy]

Heyy can anyone pls solve ques 6 of this chem atp paper..i ll be really grateful..thanks
http://www.xtremepapers.me/CIE/Cambridg ... _qp_42.pdf

 

[abcde]

The link is broken.

 

[abcde]

Why is it said that if the volume of the titre used is small, the experiment (titration) would be largely inaccurate? =S

 

[thewantedguy]

.oopsss..sorry..
http://www.xtremepapers.me/CIE/Cambridg ... _qp_42.pdf

 

[xhizors]

i need help
Q7 http://www.xtremepapers.me/CIE/Cambridg ... _qp_41.pdf

and plz sme1 chck my graph

 

[xhizors]

difference between ppt and solution ??

and in excess NaOH is zn is soluble or not

and Q10 d2

http://www.xtremepapers.me/CIE/Cambridg ... _qp_41.pdf

 

[intelnehalem]

Why is it said that if the volume of the titre used is small, the experiment (titration) would be largely inaccurate? =S

I think this is because there is a larger chance for an error to occur :unknown: Not sure about this What does the MS say ?
All the best!

 

[xhizors]

please someone help help help help , no one helps bad..

 

[scouserlfc]

Dont worry im on ur Question mate ill be back and ill see ur answer.No matter i may be a junior then u but ive got guts too handle CHem now also,so wait abt 10 - 15 mins if u come online

 

[zain786]

how long does it AVERAGELY take to do one titration question in atp chemistry?????

 

[scouserlfc]

i think if u have like practice then it wont take 10 mins it would take approx ,
7 or 8 mins depends on diff of the question..

 

[superfly]

Q6) Water containing a little dilute sulphuric acid was electrolysed, using carbon electrodes.
If 20 cm3 of oxygen were produced, what was the volume of hydrogen produced?
(a) 10 cm3
(b) 20 cm3
(c) 30 cm3
(d) 40 cm3
i noe itx answer is 40 bt i cant convince myself enuf how i came up wid this answer.. cud any1 help??

u have to check the number of moles n stuff as oxygen comes from hydroxide n nt from O2-. im nt sure abt the exact procedure myself lol bt i think im right haha!

 

[abcde]

Heyy can anyone pls solve ques 6 of this chem atp paper..i ll be really grateful..thanks
http://www.xtremepapers.me/CIE/Cambridg ... _qp_42.pdf

Since the graph for Q is steeper, the concentration of HCl should be greater than 0.1mol/dm3. That leaves you will options (b) and (d). Now notice that the volume of hydrogen produced in Q is double that in P. So the number of moles of hydrochloric acid (limiting reagent) used must be double that in P to produce this. In option (b) the number of moles of hydrochloric acid is double.
Hope this helped.

 

[xhizors]

well kal paper hai mera bhae be hurry

 

[Nibz]

Why is it said that if the volume of the titre used is small, the experiment (titration) would be largely inaccurate? =S

A lower value for the titre increases the error, as the 'overall measurement inaccuracy percentage' becomes larger!
Using less concentrated solution would make the experiment(titration) more accurate!
Hope it's clear now!

 

[abcde]

How come? How does the overall measurement inaccuracy percentage larger? Please elaborate!

 

[VelaneDeBeaute]

difference between ppt and solution ??

and in excess NaOH is zn is soluble or not

and Q10 d2

http://www.xtremepapers.me/CIE/Cambridg ... _qp_41.pdf

So sorry 4 the delay.!
Anywayz
a ppt is the solid product and a solution is a solvent+solute....they both r different terms...dunno how u mixed 'em both.!

remember
if we add Zn in NaOH-it gives white ppt but isnnt soluble
However...if v add excess it is soluble.!

In aqueous ammonia...Zn added to it will form Zn(OH)2 and will there4 dissolve...so there's no need 4 excess...REMEMBER>..Zn(OH)2 is not the ppt...cuz ppt r insoluble stuff...!!

As 4 ur 3rd question.......

H2SO4 + 2NaOHNa2SO4+2H2O
So that means 1 mole of sulfuric acid reacts wid 2 moles of sodium hydroxide
The molarity formula states
M1v1/n1=m2v2/n2
‘m’ is the molarity or concentration;
‘v’ is the volume titrated;
‘n’ is the number of moles picked 4m the equation….
So we consider the left hand side as 4 sulfuric acid and the right one 4 sodium hydroxide.
Now put in the values
M1(we need to discover) X 22/1000 (to convert to dm3-the ans u found in c2) / 1 (nbr of moles)
= (1 X 20/1000)/2
Wen calculated it becums 0.45 mol/dm3 that’s the answer..!