Biology; Chemistry; Physics: Post your doubts here!

[syed1995]

Describe How oxygen is obtained from air? (5 Marks)

 

[Spidey21]

No idea dude .. no Marking scheme available....

let me paste the question here again .. and get opinions of others as well ..




what will be the answer to part (e) guys ???

my guess would be
Bromine

 

[kitecrystal]

2003.

then its carbon,as is ALSO written in redspot

 

[syed1995]

my guess would be
Bromine

Bromine and Sulphur are incorrect, that's what the examiner report said. no MS available. I think it should be carbon too, was thinking of iodine before, cuz of its proton number

 

[MustafaMotani]

exactly .. will it happen or not? if not , then why not?

Reaction wont happen because K2O is quite stable oxide and it cant be reduce wid carbon dioxide

 

[syed1995]

then its carbon,as is ALSO written in redspot

Excellent!

 

[MustafaMotani]

Bromine and Sulphur are incorrect, that's what the examiner report said. no MS available. I think it should be carbon too, was thinking of iodine before, cuz of its proton number

Its carbon remember diamond and graphite

 

[SALT]

Important question... merchants guess paper says Dehydration.... what are we supposed to know about it reply please????

dehydration is simply the opposite of the hydration of alkenes, eg. wen ethanol is dehydrated, water and ethene are produced:
C2H5OH--->C2H4+H2O

 

[kitecrystal]

Which type of compound will liberate ammonia when heated with ammonium sulfate?
A an acid
B an alkali
C a reducing agent
D a salt
plz do mention the reason of ur choice as well..

 

[syed1995]

Under what conditions does water react with

1. Sodium
2. Magnesium

Water reaction with metals need conditions ?

what would they be ? Sodium - In All conditions the reaction will happen .. Mg - the water needs to be hot?

 

[syed1995]

Which type of compound will liberate ammonia when heated with ammonium sulfate?
A an acid
B an alkali
C a reducing agent
D a salt
plz do mention the reason of ur choice as well..

B Alkali .. its a fact dude ..

Ammonium Salts + Base --heat--> Ammonia + Water

 

[kitecrystal]

Describe How oxygen is obtained from air? (5 Marks)

someone give the precise answer,i also want to know it........

 

[kitecrystal]

B Alkali .. its a fact dude ..

Ammonium Salts + Base --heat--> Ammonia + Water

oh!ok

 

[Spidey21]

oh sorry i typed wrong i meant Iodine is the correct answer..

Bromine and Sulphur are incorrect, that's what the examiner report said. no MS available. I think it should be carbon too, was thinking of iodine before, cuz of its proton number

 

[MustafaMotani]

Under what conditions does water react with

1. Sodium
2. Magnesium

Water reaction with metals need conditions ?

what would they be ? Sodium - In All conditions the reaction will happen .. Mg - the water needs to be hot?

magnesium reacts with steam only

 

[Iridescent]

Under what conditions does water react with

1. Sodium
2. Magnesium

Water reaction with metals need conditions ?

what would they be ? Sodium - In All conditions the reaction will happen .. Mg - the water needs to be hot?

For magnesium, water should in the form of steam.

 

[Spidey21]

B Alkali .. its a fact dude ..

Ammonium Salts + Base --heat--> Ammonia + Water

for example NaOH as in the test for ions?

 

[syed1995]

oh!ok

Its one of the principal reactions which bases do .. likes acids have with metals, bases and carbonates. check the bases topic it should be on top there

 

[Spidey21]

then its carbon,as is ALSO written in redspot

it should be iodine no??
they are talking about molecular structure keeping in mind one molecule!

 

[syed1995]

for example NaOH as in the test for ions?

Yea exactly!

Test for NH4+ proves it too.