Chemistry: Post your doubts here!

[Namehere]

Wrong! Everything in every science is fully logic based. We, students, tend to ignore the logic in finding shortcuts/ways things are easy for US to remember/explain.

You stand up for the chemists Abby!

 

[AbbbbY]

You stand up for the chemists Abby!

No ones molesting the one subject I love on my watch.

 

[chocolate_girl]

Can someone tell me how do we know how many significant figures v have to use in chem and other subjects(bio, phy)

 

[daredevil]

Can someone tell me how do we know how many significant figures v have to use in chem and other subjects(bio, phy)

normally we are required to write in 3 s.f. unless otherwise stated in the question.

 

[Namehere]

Abbby, or anyone...

Could someone explain me (in enough detail so I understand, rather than memorize) Q6f(ii) & (iii).

Thank you in advance!

 

[chocolate_girl]

normally we are required to write in 3 s.f. unless otherwise stated in the question.

Is this rule applicable that you write ans in max sig fig mentioned in some value given in question?

 

[chocolate_girl]

why would we add cl in double bonds?
Cl will add in double bonds as result of electrophilic addition. whereas the mechanism of substitution is very different.
there are two carbons and one oxygen. the carbons has four electrons available for bonding. oxygen has 2 electrons available for bonding. the sequence is Carbon-Carbon-Oxygen
so carbon C=C=O will be most feasible structure.
View attachment 40495
as the chain is straight the shape is linear.

Thanks
Also
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_21.pdf
Question 3 d)
Isnt the salt in this part CaCl2 as they have referred to first reaction and that is formation of calcium chloride

 

[mehria]

Thanks
Also
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_21.pdf
Question 3 d)
Isnt the salt in this part CaCl2 as they have referred to first reaction and that is formation of calcium chloride

Look at the chart... reaction 1 is when W changes to Z
W is Ca(NO3)2 n Z is CaSO4
For reaction 1 we have to chnge calcium nitrate into calcium sulfate... so other than an acid we can use sodium sulfate or potassium sulfate as they r the only soluble sulfates....

 

[AbbbbY]

Abbby, or anyone...

Could someone explain me (in enough detail so I understand, rather than memorize) Q6f(ii) & (iii).

Thank you in advance!

This same question has been bothering me for a while. This and the weird boxes one in the organic flowchart sorta thing in variant 42 I believe. These ON13 papers at large have been very, very weird. I dearly hope this isn't the case in like a week. Difficult is okay, but this shit is a whole new level of twisted.

 

[sudeep1097]

Can anyone help me with this 3 (ii)? And can you tell me how reducing power or oxidising power is affected (increases or decreases) in oxides of these elements. (general trend?)

answer is : S or C or N or P

 

[Namehere]

This same question has been bothering me for a while. This and the weird boxes one in the organic flowchart sorta thing in variant 42 I believe. These ON13 papers at large have been very, very weird. I dearly hope this isn't the case in like a week. Difficult is okay, but this shit is a whole new level of twisted.

"Difficult is okay, but this shit is a whole new level of twisted." Hhahahahahhaa, for sure its nothing too bad, Its just not taught anywhere in the syllabus!!

 

[AbbbbY]

"Difficult is okay, but this shit is a whole new level of twisted." Hhahahahahhaa, for sure its nothing too bad, Its just not taught anywhere in the syllabus!!

I mean, look at ON13 Math P3. WHAT IN THE EFFS WORLD IS ALL THAT?!
A was at 60% or so in that particular paper. I got like 40. Lool.

 

[daredevil]

Is this rule applicable that you write ans in max sig fig mentioned in some value given in question?

yes it is.... especially when u have collected data and stuff like in prcticals or practical related questions.

mostly we use significant figures when doing calculations like maybe finding the Kc or sth.... if it is called for however u ought to use the no of significant given in the question.

 

[princeali97]

Wrong! Everything in every science is fully logic based. We, students, tend to ignore the logic in finding shortcuts/ways things are easy for US to remember/explain.

No.The thing is we have to imagine some things.In Japan and many other developed countries explanations are done using special models and very advanced media.We(especially the South east Asians) have to imagine all the things.We dont exactly visualize what happens.But still its true that South east asians score better than rest of the world

 

[Namehere]

No.The thing is we have to imagine some things.In Japan and many other developed countries explanations are done using special models and very advanced media.We(especially the South east Asians) have to imagine all the things.We dont exactly visualize what happens.But still its true that South east asians score better than rest of the world

Thats cuz you study 24/7 (just kidding)

 

[Namehere]

I mean, look at ON13 Math P3. WHAT IN THE EFFS WORLD IS ALL THAT?!
A was at 60% or so in that particular paper. I got like 40. Lool.

60% or 60 marks? Because I´ve looked at the GT and its 62 marks for an A ^^

 

[Namehere]

Abbby, or anyone...

Could someone explain me (in enough detail so I understand, rather than memorize) Q6f(ii) & (iii).

Thank you in advance!

https://www.xtremepapers.com/community/threads/chemistry-post-your-doubts-here.9859/page-404

I still need the help for that question. Winter 2013 P43

 

[faizay warsi]

^ whats the Question NO.

 

[AbbbbY]

60% or 60 marks? Because I´ve looked at the GT and its 62 marks for an A ^^

45-47 marks. ON13 32

 

[Namehere]

^ whats the Question NO.

The question is on the link I wrote. Its the only one with attachements. Its winter 2013 P43 Q6f(ii) and (iii).