Chemistry: Post your doubts here!

[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).

 

[mehria]

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?)
View attachment 40556
answer is : S or C or N or P

MnO4-, CrO42- ,Cr2O72- , HNO3, HClO4 ,HClO, NaClO, H2SO4, halogens, potassium nitrate, and nitric acid. are oxidising agents
where as halides, earth metals, formic acid, and sulfite compounds are reducing agents
hydrogen gas acts as an oxidizing agent when it combines with metals and as a reducing agent when it reacts with nonmetals

in ths question the answer can't be P... CO, NO, NO2 n SO2 or SO3 are all reducing agents

 

[princeali97]

Thats cuz you study 24/7 (just kidding)

hehe watever

 

[Mohammed salik]

MnO4-, CrO42- ,Cr2O72- , HNO3, HClO4 ,HClO, NaClO, H2SO4, halogens, potassium nitrate, and nitric acid. are oxidising agents
where as halides, earth metals, formic acid, and sulfite compounds are reducing agents
hydrogen gas acts as an oxidizing agent when it combines with metals and as a reducing agent when it reacts with nonmetals

in ths question the answer can't be P... CO, NO, NO2 n SO2 or SO3 are all reducing agents

gr8

 

[mehria]

gr8

thnk u ^.^

 

[sitooon]

45-47 marks. ON13 32

abby do the questions in P3 /m2 have to be in order ? or can we make our own?

 

[AbbbbY]

abby do the questions in P3 /m2 have to be in order ? or can we make our own?

Obviously any order. If someone doesn't know q1 they won't leave the entire paper now

 

[Suchal Riaz]

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

no the reaction one of from W to Z
W is calcium nitrate and Z is calcium sulfate.

 

[sitooon]

Obviously any order. If someone doesn't know q1 they won't leave the entire paper now

Logic
What i was doing in P1 , was making some spaces inbetween question i dont know , and then reducing the size to fit the leaved space
No the task becam easier

 

[immie.rose]

Can anybody PLEASE explain how 1: 1.33: 1.61 = 6: 8: 7 ?

 

[Namehere]

Can anybody PLEASE explain how 1: 1.33: 1.61 = 6: 8: 7 ?

View attachment 40571
View attachment 40572

I´ve already answered this question a few times... Anyways. Here what you should be careful with is the accuracy. Maintain it with 3sf. So once you divide by the smallest number and get 1 : 1.33: 1.16 ratio you just have to convert these numbers into integers. You do it through trial and error until you get all integers. If you times everything by 6 you get an integer (or atleast really close to it).

Hope it helps.

 

[sudeep1097]

MnO4-, CrO42- ,Cr2O72- , HNO3, HClO4 ,HClO, NaClO, H2SO4, halogens, potassium nitrate, and nitric acid. are oxidising agents
where as halides, earth metals, formic acid, and sulfite compounds are reducing agents
hydrogen gas acts as an oxidizing agent when it combines with metals and as a reducing agent when it reacts with nonmetals

in ths question the answer can't be P... CO, NO, NO2 n SO2 or SO3 are all reducing agents

Thanks! but mark scheme says P as well and thanks for the general examples really helpful.
But incase of only *element oxides* in the given periodic table in question is there some kind of general trend on the reducing strength of the *element oxides*?

 

[itallion stallion]

Can someone plz upload notes or link of A2 organic reactions that contain complete condition like where to warm or heat and reflux etc.
Thanks in advance!

 

[itallion stallion]

Can someone plz help me with this May June 2010 paper 41 question 5ai, why are we not taking left electrode potential as +0.83v?Again in part B why not take Eo at cathode to be +0.13v.
Thanks in advance!

 

[sadiaali]

Please anyone do question Q 28 for me.Why cis-trans isomerism at the C=C double bond?
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_13.pdf