Biology; Chemistry; Physics: Post your doubts here!

[***amd***]

Can someone describe aluminium manufacturing briefly? Can't find it's notes. That AlO+Bauxite.

Aluminium ore = Bauxite (Al2O3.2H2O) [melting point - 1900 C]
Bauxite is dissolved in cryolite (Na3AlF6) to lower the melting point [900 C]

The ineer surface of electrolytic chamber = graphite cathode
Graphite anodes are hung in the electrolyte.
Al3+ ions are reduced at cathode, and molten Aluminium is produced, which seeps out from a tap/or whatever, just an opening in the base of chamber.
O2- ions oxidised at anode. Oxygen there reacts with anode, though graphite is inert elctrode but this happens coz of high temperature, and CO2 is produced.

 

[***amd***]

dhuk dhuk
dhuk dhuk
3 hrs 30 minutes left

 

[Laibaaa]

dhuk dhuk
dhuk dhuk
3 hrs 30 minutes left

Ekh. Have to go to school at 8 so like 2 hours left. :'(
I feel like i literally don't know a thing.

 

[***amd***]

What exactly is a "heating curve"?

it seems to be a graph, ny its name, with a label of temperature or heat provided on either of the axes.

 

[***amd***]

Ekh. Have to go to school at 8 so like 2 hours left. :'(
I feel like i literally don't know a thing.

school? during exams? :O

 

[Laibaaa]

school? during exams? :O

Umm I meant my centre. My Cie centre is at my school so

 

[***amd***]

Umm I meant my centre. My Cie centre is at my school so

oh, achha.

 

[***amd***]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s12_qp_22.pdf
Q1 f
how come the answer is Ca?

 

[Faizan Muhammmad]

my teacher's notes say, it doesn't.

it does
with water it forms hydroxide
with steam oxide

 

[***amd***]

it does
with water it forms hydroxide
with steam oxide

but thats what i ve studied .-.

 

[Faizan Muhammmad]

but thats what i ve studied .-.

koee nae hota hai aisay bhee

 

[Laibaaa]

The answer to this is D.

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s12_qp_22.pdf
Q1 f
how come the answer is Ca?

Number of electron shells = period.
4 shells so 4th period, go check it in the periodic table, Ca is in the 4th period.

 

[peacce]

guys monomer mei double bond hta and polymer mein single na?

 

[peacce]

Polymer can be unsaturated too (have double bonds) eg vegetable oil.

-_- .. i suck at organic chemstry man

 

[peacce]

Also - what exactly is Ionic precipitation? Precipitation of insoluble salts? I know all about salts - but it's this name I havent fully grasped.

m not good at chapter "SALTS"

 

[peacce]

Learn the solubility chart. See reactions and compare how it is applied on reactions (identify whether salt is insoluble or soluble) and read up on how to prepare it. That's the best you can do atnow.

solvd PstpaperS?

 

[peacce]

Yeah yea i have

 

[sameersuleman]

You still got 1.30 hours. More than enough

However, structures I have encountered till now have been same as urs eg. ethene to polyethene. Just remove double bond and put continuation bonds either side. Don't worry you'll do great

Man I think you're talking about Addition polymers... non of them have a double bond while condensation may contain e.g C=O bond

 

[peacce]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s13_qp_22.pdf
Q.B7 part a ? draw it for me pls :?

 

[***amd***]

Allah Hafiz
best of luck, dont forget to recite Ayat 4 of Surah Al Fatihah. I