Chemistry: Post your doubts here!

[A star]

That's correct. But Mg only very slightly hydrolyzes.. so if one writes no reaction or very slow reaction he should get the mark.

u know a METAL or a NON metal dont hydrolize in water their COMPOUNDS hydrolize so dont mix the two up

 

[knowitall10]

CAN YOU TELL ME REACTIONS OF GROUP II AND PERIOD III WITH HCL AND H2O AND THEIR PH AND OBSERVATION IT IS CONFUSING

or download this revision guide; its an excellent summary of everything.
http://www.hoddereducation.co.uk/Ti..._A_Level_Chemistry_Revision_Guide_for_CIE.htm

 

[knowitall10]

May june 11 53
1d(iiii)

the mark scheme says temp of both reagents taken or temp taken immediately after mixing.
What exactly is your question?

 

[ZainH]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_21.pdf

Q2)d)

Isn't reaction 1 the one where Ca goes to CaCl2? How would a solouble sulfate be an appropriate reagent? Explanation please

 

[syed1995]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_21.pdf

Q2)d)

Isn't reaction 1 the one where Ca goes to CaCl2? How would a solouble sulfate be an appropriate reagent? Explanation please

HAHA ANOTHER ONE! .. atleast i am not alone over here.. I also didn't read the reaction 1 word written in the table when i first read it.. I practically read the table 3-4 times but still didn't find where reaction 1 was.. But a guy on XPF helped me...

http://puu.sh/2NhNW.png

Check the W--> Z reaction.. that's labelled as reaction 1 .. Nitrate to Sulfate...

 

[knowitall10]

Oh my God. I give in! Can someone please tell me where on earth to we place the thermometer when we're drawing the apparatus in Paper 5, M/J 11 v3 Q1 (c)? (I take my reply to Tkp back- i think i get what he's asking...)

 

[ZainH]

HAHA ANOTHER ONE! .. atleast i am not alone over here.. I also didn't read the reaction 1 word written in the table when i first read it.. I practically read the table 3-4 times but still didn't find where reaction 1 was.. But a guy on XPF helped me...

http://puu.sh/2NhNW.png

Check the W--> Z reaction.. that's labelled as reaction 1 .. Nitrate to Sulfate...

Oh wow.. How the he- ?
...
Laaaaaaame, alteast I'm not alone xD . Thanks btw.

 

[knowitall10]

Oh my God. I give in! Can someone please tell me where on earth to we place the thermometer when we're drawing the apparatus in Paper 5, M/J 11 v3 Q1 (c)? (I take my reply to Tkp back- i think i get what he's asking...)

and even if i finally manage to draw the apparatus based on my AS practicals, how do we heat the solution? Can someone please draw a neat diagram?

 

[Soldier313]

ok see...

O2/OH^- = 0.4V and F/F^- = 2.87 so OH ion is easier to be oxidized than F^- so O2 will form at the anode..got it ? BUT i don't know why the mark scheme gives a wrong answer to this method with Br not SO4 but for the cations it gives all the answers right..do u solve it that way too?

exactly, that's my confusion, using the same method with Br gives a diff answer :/

 

[iKhaled]

exactly, that's my confusion, using the same method with Br gives a diff answer :/

using the other method that i showed u gives all of them correct values but i wonder why they dont give the same values with the potential electrodes if anyone here knows why or u know why then please do tell me because i want to know the reason now too..

 

[falcon678]

guys question 14...can u please explain how??

 

[ZainH]

What are the reagents/conditions for an elimination reaction and why?

 

[falcon678]

What are the reagents/conditions for an elimination reaction and why?

H2SO4 and alcoholic NaOH for elimination.......i dun knw y thou...

 

[knowitall10]

guys question 14...can u please explain how??

Write down the reaction of each of the four choices and use the mole ratio to figure out the masses. then see the mass of the gas produced and you'll get the answer. it's a long working but pretty simple.

 

[falcon678]

Write down the reaction of each of the four choices and use the mole ratio to figure out the masses. then see the mass of the gas produced and you'll get the answer. it's a long working but pretty simple.

thanks!

 

[ZainH]

H2SO4 and alcoholic NaOH for elimination.......i dun knw y thou...

Hm, what about the condition?

 

[Tkp]

the mark scheme says temp of both reagents taken or temp taken immediately after mixing.
What exactly is your question?

actually i didnt get for the 1 d iv
cn u please explain it?didnt get the part thats written in the ms

 

[Soldier313]

Aoa wr wb
need some detailed explanation on how to do qn 3 c of this paper pleaseeee

Using the method for electrode potential values, we don't get the answers exactly as the ms says

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_42.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_ms_42.pdf


PhyZac PANDA-
@everyone else taking A2

JazakAllah khair

 

[PhyZac]

Aoa wr wb
need some detailed explanation on how to do qn 3 c of this paper pleaseeee

Using the method for electrode potential values, we don't get the answers exactly as the ms says

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_42.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_ms_42.pdf


PhyZac PANDA-
@everyone else taking A2

JazakAllah khair

Waalikum Assalamu Wa Rahmatullahi Wa Barakatoho.

Well, for the cathode it worked perfectly.
Those cation which are less reactive than hydrogen (that is +ve E values) will form, as in Ag, while if not, then hydrogen forms.

Anion din't work with me either. But I always learned the when sulphate is there O2 is formed. Sorry. Rest I am confused too.

 

[megamind]

how to explain that a compound is cis or trans

if two big side chain point in same dirction its cis
trans is other way round