Chemistry: Post your doubts here!

[Mathemagical]

why is 2 wrong?
More H+ concentration = more acidic ... so why is it wrong?

HCO2H dissociates into H+ and HCO2- ions, so there is only one mole of hydrogen ions per mole of methanol acid.

 

[shazmina]

The 58.5 kg is for NaCl (limiting reactant). The other reactant H2O is treated as an excess reactant.

I'll look at the W04 question and post here later.

At this moment, I am tempted to dismiss it as a typo in the marking scheme, because if the answer is indeed B instead of D, it would be wrongly answered by many students. This will mean that it would have to be discussed in the examiners' report (which it wasn't).

Furthermore, it was poor practice to present the options without putting the room temperature curve on the same axis for comparison. I believed they will be more careful about making it less ambiguous in recent years.

ohkkk thank you

Sure ... please check and let me know , thanks alot

 

[princess Anu]

ohkkk thank you

Sure ... please check and let me know , thanks alot

In D, the area doesn't look similar to the area given in the diagram of the question, it seems less.. therefore I promptly selected option B :s
Moreover, If you look closely, the graph given doesn't have its line extending beyond the x axis, whereas in B it is + the peak has displaced downwards showing that the graph has indeed moved rightwards & downwards ..

am I wrong Metanoia ?

 

[shazmina]

In D, the area doesn't look similar to the area given in the diagram of the question, it seems less.. therefore I promptly selected option B :s
Moreover, If you look closely, the graph given doesn't have its line extending beyond the x axis, whereas in B it is + the peak has displaced downwards showing that the graph has indeed moved rightwards & downwards ..

am I wrong Metanoia ?

ahan.... so thats the reason..

 

[mohhef3]

The following half reactions occur when potassium iodate(V), KIO3, in hydrochloric acid solution oxidises iodine to ICl 2 – .
IO3 – + 2Cl – + 6H+ + 4e– → ICl 2 – + 3H2O I2 + 4Cl – → 2ICl 2 – + 2e– What is the ratio of IO3 – to I2 in the balanced chemical equation for the overall reaction?
A 1: 1 B 1 : 2 C 1 : 4 D 2 : 1
someone help me out with this que answer is b.its paper 12 nov 2013

 

[Metanoia]

In D, the area doesn't look similar to the area given in the diagram of the question, it seems less.. therefore I promptly selected option B :s
Moreover, If you look closely, the graph given doesn't have its line extending beyond the x axis, whereas in B it is + the peak has displaced downwards showing that the graph has indeed moved rightwards & downwards ..

am I wrong Metanoia ?

Honestly, its just as likely that D was the answer and we are running in circles trying hard to justify B.

If I assume they are plotted on the same scale, and overlay the two graphs....if B was really the intended answer, would it be fair for students to see the very very slight shift to the right?Maybe you are on to something with the focus on the area, but it can be optically misleading.
If I were to take the exam that year, I would honestly say I would have chosen D at that moment (and possibly gotten it wrong).

Lets just hope the paper for this year avoids such ambiguity.

 

[kesha27]

Please help with these nov 2014 p13

 

[shazmina]

Honestly, its just as likely that D was the answer and we are running in circles trying hard to justify B.

If I assume they are plotted on the same scale, and overlay the two graphs....if B was really the intended answer, would it be fair for students to see the very very slight shift to the right?Maybe you are on to something with the focus on the area, but it can be optically misleading.
If I were to take the exam that year, I would honestly say I would have chosen D at that moment (and possibly gotten it wrong).

Lets just hope the paper for this year avoids such ambiguity.

View attachment 54618

I hope the same too ...

 

[shazmina]

Help please ...

Which gas is likely to deviate most from ideal gas behaviour?

A HCl
B He
C CH4
D N2

The Ans is A ...
How do we know that HCL deviates most from the ideal gas behaviour ... do we have to memorise this or is there anyway we can find out ? please helpp

 

[princess Anu]

Please help with these nov 2014 p13

if the Ans is D...

 

[princess Anu]

Help please ...

Which gas is likely to deviate most from ideal gas behaviour?

A HCl
B He
C CH4
D N2

The Ans is A ...
How do we know that HCL deviates most from the ideal gas behaviour ... do we have to memorise this or is there anyway we can find out ? please helpp

I think we have to look at the number of electrons.. the one with greatest number of e or the greatest MR will have the greatest strength of VWW forces of attraction

 

[asadalam]

If a compound has a ring in it,does that mean all bonds will be at angles and there will be no possibility of Cis Trans at any double bond inside the ring?
Metanoia

 

[The Sarcastic Retard]

Help please ...

Which gas is likely to deviate most from ideal gas behaviour?

A HCl
B He
C CH4
D N2

The Ans is A ...
How do we know that HCL deviates most from the ideal gas behaviour ... do we have to memorise this or is there anyway we can find out ? please helpp

HCl have most difference b/w electronegativity... (PRESENCE OF FORCE OF ATTRACTION)

 

[shazmina]

I think we have to look at the number of electrons.. the one with greatest number of e or the greatest MR will have the greatest strength of VWW forces of attraction

HCl have most difference b/w electronegativity... (PRESENCE OF FORCE OF ATTRACTION)

So basically its like we have to see the forces between the atoms in the compound eh?

Thank you both of you

 

[The Sarcastic Retard]

So basically its like we have to see the forces between the atoms in the compound eh?

Thank you both of you

We are asked to find the which deviates most from ideal gas behaviour.
one postulate of ideal gas is, it doesnt have inter molecular orce of attraction.. HCl was the strongest in this reason which makes you sure that it devieates most

ignore spell errors

 

[shazmina]

We are asked to find the which deviates most from ideal gas behaviour.
one postulate of ideal gas is, it doesnt have inter molecular orce of attraction.. HCl was the strongest in this reason which makes you sure that it devieates most

ignore spell errors

Lol thats okay ... i understood clearly ... thank you soo much

 

[princess Anu]

why B?

 

[shazmina]

why B? View attachment 54631

Because Compound B has the greatest number of C-H bonds...
do check for all other compounds ... and finally u will come to the conclusion as B
We studied this in Biology

 

[princess Anu]

why not D? :S

 

[princess Anu]

Because Compound B has the greatest number of C-H bonds...
do check for all other compounds ... and finally u will come to the conclusion as B
We studied this in Biology

yeah but why don't we consider C-O bonds too?