CHEM AND BIO HELP AND TIPS HERE

[holtadit]

The usual man, zinc and copper.


SO does the electrolyte's blue colour fade ?

[DEGO]

if electrode is copper then it won't because cu ions tht lost from the solution to cathode replaced with one's from anode  till anode all dissolve thn reaction stop
am not sure if the electrode is zinc but i guess the same

[holtadit]

Actually never mind the above doubt. I made a mistake... i figured it out myself.

Heres another one...


How would you describe a liquid alkane ? Does it have a particular smell or any features that you could observe directly ? I am talkin with reference to the analysis part of Paper 6.

When lead nitrate and potassium iodide are reacted what is the name of reaction that takes place ? Is it precipitation or double displacement ?

[DEGO]

Actually never mind the above doubt. I made a mistake... i figured it out myself.

Heres another one...


How would you describe a liquid alkane ? Does it have a particular smell or any features that you could observe directly ? I am talkin with reference to the analysis part of Paper 6.

When lead nitrate and potassium iodide are reacted what is the name of reaction that takes place ? Is it precipitation or double displacement ?

precipitation i guess lead iodide is yellow ppt 

[holtadit]

I thought so too, but this kharban MS from 1992 said double displacememnt. Its not even the real MS !!

[sarasa]

The term double diplacement can also be used for a precipitation reaction since they are exchanged.
For the above reaction:
Lead nitrate + potassium iodide=> lead iodide + potassium nitrate
So u see here potassium took the nitrate and lead took the iodide
It is a precipitation reaction since lead iodide is insoluble just as everyone said.
Overall we can say any precipitation reaction is also a double displacement!

[haris94]

Actually never mind the above doubt. I made a mistake... i figured it out myself.

Heres another one...


How would you describe a liquid alkane ? Does it have a particular smell or any features that you could observe directly ? I am talkin with reference to the analysis part of Paper 6.

When lead nitrate and potassium iodide are reacted what is the name of reaction that takes place ? Is it precipitation or double displacement ?

here's what i know:
alkanes r colourless
are less dense than water (will float in water)
have low melting and boiling points
insoluble in water

hope it helps

[sarasa]

 I know the analysis question about the alkanes. It said in one paper 6 that substance F I guess smells like petrol what can you conclude of the nature of F?
This is how I understand it, since all fractions of petroleum are alkanes and petrol is a fraction of petroleum therefore petrol is an alkane and hence this substance smells like petrol, it would definitely be an organic substance most probably an alkane!
Hope this helped!

[holtadit]

I know the analysis question about the alkanes. It said in one paper 6 that substance F I guess smells like petrol what can you conclude of the nature of F?
This is how I understand it, since all fractions of petroleum are alkanes and petrol is a fraction of petroleum therefore petrol is an alkane and hence this substance smells like petrol, it would definitely be an organic substance most probably an alkane!
Hope this helped!

Thanks. I remember that question too, thats why I was asking if there were any other things that could be used to identify them.


Heres anothery query:

 SO3 + H2O -> H2SO4                  This reaction only involves reduction, right ? No oxidation and hence its not a redox reaction ?

[Amr Fouad]

Thanks. I remember that question too, thats why I was asking if there were any other things that could be used to identify them.


Heres anothery query:

 SO3 + H2O -> H2SO4                  This reaction only involves reduction, right ? No oxidation and hence its not a redox reaction ?

No..to begin with..you must know that it is not possible to have reduction without oxidation, or vice versa...thats y it is called REDOX..

In this reaction, there is no reduction or oxidation..and so its not a redox

SO^3.....X+(6x-2)=0
so X=+6

H^2SO^4 :

SO^4 has a charge of -2.

so X+(4x-2)=-2

again X=+6..

therefor no reduc, no oxid, no redox..

hope that helped

[holtadit]

Yeah... i see.


Thanks again man ! 

[saleemsamer]

would some1 plz care to explain the following from the bio syllabus:

- explain enzyme action in terms of the ‘lock
and key’ model

- outline the use of microorganisms and
fermenters to manufacture the antibiotic
penicillin and enzymes for use in biological
washing powders

- describe the role of the fungus Penicillium in
the production of antibiotic penicillin

 

[Amr Fouad]

Yeah... i see.


Thanks again man ! 

any time dear mate

[DEGO]

would some1 plz care to explain the following from the bio syllabus:

- explain enzyme action in terms of the ‘lock
and key’ model

- outline the use of microorganisms and
fermenters to manufacture the antibiotic
penicillin and enzymes for use in biological
washing powders

- describe the role of the fungus Penicillium in
the production of antibiotic penicillin

 

1) each enzyme has its own substrate tht is complementary to its active site (like key and lock)
2)enzyme in washing powder:
a)protease use for protean stains and lipase for fat and greasy stains
b) put micro organism (bacteria or fungi) in fermenter with optimum conditions to reproduce (asexual):
1)temp.( by cold water or steam)
2)sugar --> energy
3)ammonia ---> nitrogen for protean
4)air
5)salt --> help metabolic reaction
6)light for algae i used


if u need the fungi it is filtered after this process (residue)
if u need the enzyme it will be in the filtrate
the penicillin is made from Penicillium

[holtadit]

CnH2n+2(g) + (1.5n+0.5)O2(g) nCO2(g) + (n+1)H2O(g)


Thats the formula to balance the equation for the burning of an ALKANE

Whats the quick method for ALCOHOL and ALKENE