Chemistry Variant 32 Paper Discussion

[Ashay]

dont they ask why the number decreases ? i put its bcs its killed by high conc of ethanol and the number increases because the yeast cells multiply and reproduce. is it correct ?:/

No they asked why it increases.

 

[Tekno-M]

What are the two reasons for using cryolite...?

I wrote decrease temperature, so (1): decrease heating power cost, and (2) does not burn off the carbon electrode that quickly...

Cryolite decreases the melting point of alumina (1) and increases its conductivity (2)

 

[Tekno-M]

What is another catalyst, other than yeast for the starch --> simple sugar thing?
Is it H2SO4..?

HCl

 

[Tekno-M]

What I wrote was Fe (III) was formed which is reddish brown in color. - For the last question

Same, but I think they're gonna deduct something there, because Fe(III) is an ion, an ion can't just form lol.

 

[B333]

I thought the catalyst was amylase for the hydrolysis of starch
how is it hydrochloric acid?

 

[Tekno-M]

Amylase is the catalyst in the body, I don't think amylase is available for lab experiments. Hydrochloric acid can act as a catalyst for the reaction.

 

[wooowooowoo]

I thought the catalyst was amylase for the hydrolysis of starch
how is it hydrochloric acid?

They had specified 'enzyme' in the question itself so stating an enzyme does not make sense. Anyway, I do feel that they will give marks for writing an enzyme's name.
Any acid is fine (as per my teacher)

 

[Tekno-M]

They had specified 'enzyme' in the question itself so stating an enzyme does not make sense. Anyway, I do feel that they will give marks for writing an enzyme's name.
Any acid is fine (as per my teacher)

I also think that any strong acid will score the mark.

 

[AsinSana]

It wasnt hcl , it should be manganese peroxide

 

[B333]

What about the question with the advantages of biogas other than economic use?

 

[mamoon123]

What about the question with the advantages of biogas other than economic use?

It would conserve our petroleum deposits

 

[ammarmans]

I found the paper a bit hard!
How did you guys find it

 

[Vasuda Venkitakrishnan]

does ny1 have the question paper variant 32???

 

[Zoya khalid]

To form NaOH from NACL was by electrolysis?

 

[B333]

Yes it was electrolysis

 

[yousef]

the mole question = ethene C2H4

The last question = coz it got reduced from Fe3+ to Fe solid after gaining electrons from ethylamine...

Why is plastic suitable : coz its light
has high mp bp
doesnt conduct e

Al used coz strong and light and doesnt corrode

Cu used coz its a good conductor of heat
and resists corrosion so is not toxic

To form NaOH from NACL by electrolysis of Conc NACL sol... Describe etc...

The formula for the alkene that oxidises to form one acid is ethen right? C2H4??

Can i use sodium nitrate to displace Ethylamine chloride??? thanks alot!

We use cryolite to decrease mp of al2O3 so that less energy is needed and to make it conduct better because al2O3 has a protective oxide layer bla

no friend it was c5 h 10 it wasnt ethene

 

[Tekno-M]

How can Al2O3 have a protective oxide layer? Al2O3 IS the oxide layer of aluminium, you cannot say that Al2O3 is covered with Al2O3... And plastic is flexible too.

 

[B333]

what did you guys write for the question about the rates of reactions why the order of experiments A,B,C and D was in the order you said it was?

 

[mamoon123]

what did you guys write for the question about the rates of reactions why the order of experiments A,B,C and D was in the order you said it was?

I don't really remember, but the one that took the least time was the fastest, and the one that took the greatest time was slowest.

 

[B333]

oh okay what did you write for the reason why graphite is slippery?