Qualification > Sciences
CHEM AND BIO HELP AND TIPS HERE
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:
--- Quote from: Ari Ben Canaan on April 10, 2010, 03:35:21 pm ---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 ?
--- End quote ---
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:
--- Quote from: sarasa on April 10, 2010, 04:43:03 pm --- 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!
--- End quote ---
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:
--- Quote from: Ari Ben Canaan on April 11, 2010, 01:20:06 pm ---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 ?
--- End quote ---
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
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