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Edexcel AS chem, Unit 2 inorganic industrial processes

I'm doing the edexcel specification but can't seem to find exact figures for the conditions needed for each of the industrial processes listed... please help! I know different textbooks have different figures, and the temp. etc. changes with different stages, but does anyone have any final figures? so far I have:

NH3- 400c, 200atm -> Haber process
HNO3- ??? -> Conversion to nitric acid
H2SO4- 450c, 2atm -> The contact process
Al- 970c, 1atm -> electrolytic extraction of Al
Cl- ??? -> electrolysis of sodium chloride

I'd also greatly appreciate it if someone could tell me how much detail of the above processes we need to know- I have acquired 1-2 pages from lessons on each 1, :s-smilie:

with several different equations per process...I don't really think this is necessary and would'nt remember all formulae (I also have another textbook which isn't anywhere near as detailed..) Help? :unsure:

Reply 1

RMIM

haber process 400c 200atm iron catalyst

ostwald, Hno3
1. 4NH3+ 5O2 <---> 4NO + 6H20
900c 4-10atm platinum/rhodium cat
2. 2NO + O2 <---> 2NO2
3. NO2 + O2 + H2O <--> 4HNO3

contact proess, H2SO4
1. S + O2 ---> SO2
2. SO2 + O2 ----> SO3
425c 2atm catalyst: vanadium(V)oxide

<<SO3 +H2O--> H2SO4 but this is not done as a hard to condense mist is formed>> so

3. SO3 + H2SO4 ---> H2S2O7 (99.5%) (OLEUM)
4. H2S2O7 + H20 ---> 2H2SO4 (98%)

Aluminium. Bauxite (Al2O3.XH2O amphoteric + FE2O3basic + SiO2)
1.Bauxite crushed and hot 10% solution os NaOH added.
2. Iron oxide does not react as its basic. SiO2 is weakly acidic but has giant atomic structure so it does not reach. Al2O3 will react as it amphoteric

3. solids are filtered off leaving sodium aluminate
4. carbon dioxide blown in giving aluminum hydroxide
5. aluminum hydroxide heated to give AL2O3.XH2O again.

AL2O3.XH20 is dissloved in cryolite to lower melting point from 2000c to about 900c.
This is then electrolised in a cell lined with carbon acting as the cathode and carbon anodes that are lowered in.

Cathode Al3+ + 3e --> Al
Anode 2O^2- ----> O2 + 2e this oxygen reacts with carbon anode C+O2-->CO2

--
electrolysis of brine
titanium anode: 2Cl- ----> CL2 + 2e
steel cathode: 2H+ + 2e ---> H2

(all the answers were taken from edexcel past papers, i hope i did not make any mistakes - double check)

Reply 2

angelmxxx

mmm... i'm doing this syllabus and have found the cgp AS chemistry book really really good. Also i don't think you need to know the specifics about the "10% solution as NaOH is added" etc... well i hope not anyways! From my specification and my teacher, i've only heard that you just need to know what electrolyte + anode/cathode are made from, equations at both anode & cathode, and the temperatures... there's a good video/notes on the royal chem society's website that we were shown in class though =]

Reply 3

o00o

thankyou! i will use those numbers, rmim, they are kind of what my notes are like now, very short and concise..
i have the CGP book too! its much more 'to the point' than the one i, um, obtained, from school for cross-referencing lol. I was a bit worried though 'cos everyone in my class religiously uses the masses of notes we get from class, whereas my notes all come from the CGP book :smile: