Chemistry Paper 3 IGCSE Oct.Nov. 2013 Discussion

[soooso]

polymerisation reaction should be enough!

i dont think so,, bcuz it was for 2 marks ,, so u have 2 say condensation polymerisation

 

[shahdigcse]

Guys, temme the answers what you guys wrote? ​

Which form the covalent molecules, in the first question? I don't remember.​

What did you you write the answer for how photochromic glass works? It's a reversible reaction.​

Why is ammonia based something is used, though it expensive? Because it requires less electricity and more yield​

About the charcoal & coke thing? Charcoal has less carbon​

Which metals don't react with acid & how can we experiment & show & which metal forms purple/pink solution & when zinc used, what will be observed? Managanate; turns colourless​

Why is there's different concentration of AgNo3 & potassium dichromate used? Because two moles of AgNO3 react with 1 mole of potassium dichromate​

What will happen when transition metal oxidation isn't written? you cannot write the correct formula​

What was the name of reaction when glucose changed to starch? condensation polymerisation​

What was the ester, unsaturated or saturated? saturated​

-I don't remember what I wrote for this one
-Yeah I wrote the same thing and explained why it goes dark in sunlight.
-For this one I said that electricity is expensive & smthing about energy saving.
-Same.
-I don't remember.
-Same.
-Same+transition metals have more than one oxidation states.
-Same
- It was unsaturated because it didn't have the maximum number of hydrogens

 

[Skyfall19]

its

i got 0.664 grams too its right i think..also 32 variant what was the answer for the agcl question..the sunglasses one.

1.32 g 0.004 moles of Agno3 then multiply it with 2 cox it was 2 moles of agno3 0.008 then moles of k2cr2o7 divide by2 0.004 multiply by 332g given in the qstn da answr is 1.32

 

[Faheen]

Oh.... so u a paki hmm??

no just my centre

 

[fizzyy]

its
1.32 g 0.004 moles of Agno3 then multiply it with 2 cox it was 2 moles of agno3 0.008 then moles of k2cr2o7 divide by2 0.004 multiply by 332g given in the qstn da answr is 1.32

so the answer for me is 0.664, i cross-checked my answers with 25 more people after the exam and reliable sources, so i guess i am right on this one !

 

[asadqureshi]

Hey what was the answer for the question about difficulty faced due to unknown oxidation state? I wrote that we wouldn't know the concentration of compounds required for reaction. I know it's wrong but can someone tell me the correct answer?

 

[asadqureshi]

And what do you think the grade threshold for an A* will be this session?

 

[qasimnisar2121]

And what do you think the grade threshold for an A* will be this session?

i can assure you, 165-7 out of 200 will get one an A*

 

[asadqureshi]

i can assure you, 165-7 out of 200 will get one an A*

Thanks

 

[asadqureshi]

But how many marks out of 180?

 

[qasimnisar2121]

But how many marks out of 180?

ofc. it will be then 147-150 or a little more