how was chemistry p42?

[Dolly96]

I wrote hydrogen and van der waals

 

[urvi kapoor]

How many marks was the complete first question of section B

 

[Ujjwal Basnet]

I wrote acid rain for nitrate.. And fertilizers for phosphate

i think yes bcoz there are phosphate fertillizers too...i wrote amide link and ester link..because it can form hydrogen bond with water

 

[DumbIdiot]

no3- = fertiliser
po43- = detergent
so2 = contact process
difficulty in removing no3- = all of its compounds are soluble in water . cannot be precipitated
ion removed on addtion of caco3 = ba2+ and pb2+
though i found it strange that there was both ba2+ and so42-
interaction = van der waals forces between side chain of valine
and hydrogen bond between amide linkage

 

[Ujjwal Basnet]

no3- = fertiliser
po43- = detergent
so2 = contact process
difficulty in removing no3- = all of its compounds are soluble in water . cannot be precipitated
ion removed on addtion of caco3 = ba2+ and pb2+
though i found it strange that there was both ba2+ and so42-
interaction = van der waals forces between side chain of valine
and hydrogen bond between amide linkage

why ba2+ and pb2+?

 

[DumbIdiot]

why ba2+ and pb2+?

probably cuz most carbonate are insoluble in water. since caco3 is slightly soluble in water some co32- would be formed and pbco3 and bac03 would be precipitated.
i`m not sure about this though

 

[DumbIdiot]

guys for the pH question. was it 100cm^3 of 0.5moldm^-3 acid or simply 0.5mol in 100cm^3?

 

[BITTUDROCKSTAR]

guys for the pH question. was it 100cm^3 of 0.5moldm^-3 acid or simply 0.5mol in 100cm^3?

It was 100cm^3 of 0.5M acid.

 

[DumbIdiot]

It was 100cm^3 of 0.5M acid.

so there was 0.o5 mol(and not 0.5) in 100cm3 ?

M - molar concentration ,right?

 

[Raissa Christabel]

A
Addition bro there was double bond :0

yeah it was addition

 

[Cesar_malik]

why ba2+ and pb2+?

ba would be due to reactivity and would displace ca
i dont know about pb i also wrote about the other like so4 as it is negative and would react with positive

 

[Andre Sutiono]

About the polymer, it was addition. I'm pretty sure because it has already come out in past paper. btw, what did you guys answer in the design material question, it was about what can be removed with caco3 ...?

 

[nabeelah]

why ba2+ and pb2+?

in reactivity series Ca is found at the top of Pb and Ba so it would displace them from their ions...*i think*

 

[*MK*skydiver :D]

in reactivity series Ca is found at the top of Pb and Ba so it would displace them from their ions...*i think*

Lead and barium cations wud form insoluble carbonates and sulfate would form the insoluble calcium sulphate so it can be removed

 

[*MK*skydiver :D]

About the polymer, it was addition. I'm pretty sure because it has already come out in past paper. btw, what did you guys answer in the design material question, it was about what can be removed with caco3 ...?

The following question, about how does the polymer absorb water, I drew hydrogen bonds between water and the polymer..but I wasn't sure what to do with the Na+ ion in the polymer...I replaced it with a Hydrogen from the water ....

 

[*MK*skydiver :D]

How did you guys do the Bronsted lowry question? I think it was the worst question of the entire paper ....

And what other product formed in the organic question ....the last Q in section A ...

 

[Cesar_malik]

Tha

How did you guys do the Bronsted lowry question? I think it was the worst question of the entire paper ....

And what other product formed in the organic question ....the last Q in section A ...

That quest was wierd just random stuff dont remmb how did u guys do the first quest first part the electrons one i was confused how would chlorine form negative icon when nitrogen is making coordinate covalent bond lol

 

[Cesar_malik]

How did you guys do the Bronsted lowry question? I think it was the worst question of the entire paper ....

And what other product formed in the organic question ....the last Q in section A ...

What is this na+ iom quest ?? It was never completly in the monomer as I recall

 

[BITTUDROCKSTAR]

Tha
That quest was wierd just random stuff dont remmb how did u guys do the first quest first part the electrons one i was confused how would chlorine form negative icon when nitrogen is making coordinate covalent bond lol

It was NH3 reacting with HCl. So H-Cl bond was broken and the chlorine got that extra electron to form the -ve ion from the hydrogen atom. The H+ then formed the coordinate bond. I guess you didn't read the question properly. That reaction (between NH3 and HCl) was the question's first line.

 

[BITTUDROCKSTAR]

so there was 0.o5 mol(and not 0.5) in 100cm3 ?

M - molar concentration ,right?

Yes and yes.

 

[BITTUDROCKSTAR]

The following question, about how does the polymer absorb water, I drew hydrogen bonds between water and the polymer..but I wasn't sure what to do with the Na+ ion in the polymer...I replaced it with a Hydrogen from the water ....

I wasn't sure of this one either. I simply showed an ionic type interaction between the Na+ and the delta -ve oxygen and COO- and the delta +ve hydrogen. Although you may be right because the Na+ ions may leave the polymer on adding it to a solution.