Physics, Chemistry and Biology: Post your doubts here!

[TheManiac]

how to improve accuracy of an experiment ???

Repeat the experiment multiple times. If the results are consistent, the experiment becomes more accurate.

 

[TheManiac]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s12_qp_11.pdf
pls explain question 16........

http://chemistryforsg-olevel.blogspot.com/2012/01/qualitative-analysis-testing-for_02.html
i think that this table will help you

 

[MMK95]

http://chemistryforsg-olevel.blogspot.com/2012/01/qualitative-analysis-testing-for_02.html
i think that this table will help you

Thanks.....

 

[fatimanasir]

i already did bio paper 6 it was so easy

 

[ZaqZainab]

I am done with it too

 

[ZaqZainab]

Now its time for Chem and Maths

 

[fatimanasir]

Now its time for Chem and Maths

3 papers tomorrow

 

[TheManiac]

3 papers tomorrow

4 papers tomorrow ahahahhaah xD

 

[fatimanasir]

4 papers tomorrow ahahahhaah xD

omgg how come ? chem math and what ?

 

[ZaqZainab]

4 papers tomorrow ahahahhaah xD

You gotta be kidding me Poor you Best of luck

 

[TheManiac]

omgg how come ? chem math and what ?

chem p1 & p6, german and math p2

 

[ZaqZainab]

Doubt Chemistry
In question 6(g) how do you know it is manganese?
and yeah the marking scheme is kinda hard to understand sorry about it couldn't find a better one

 

[sj0007]

Doubt Chemistry
In question 6(g) how do you know it is manganese?
and yeah the marking scheme is kinda hard to understand sorry about it couldn't find a better one

While solving this paper how i came up tothe conclusion was due to the hydrogen peroxide reaction, manganese oxide is a catalyst for this reaction and moreover it is coloured so the oxide is definitly of a transition metal....hope i helped u

 

[ZaqZainab]

Is distilled water used as a solvent? for electrolysis
I have heard distilled water does not produce electricity bt i dunno about being a solvent

 

[ZaqZainab]

While solving this paper how i came up tothe conclusion was due to the hydrogen peroxide reaction, manganese oxide is a catalyst for this reaction and moreover it is coloured so the oxide is definitly of a transition metal....hope i helped u

But aren't transition elements colored? so why is T a black solid?

 

[sj0007]

But aren't transition elements colored? so why is T a black solid?

in chemistry black compounds are considered as coloured......................white compound are not considered as coloured the rest are...

 

[Eshmal]

Chemistry guess paper ??

 

[Neha Farooqi]

TELL US WHAT HAPPEND IN THE BIO PAPAER PLEEEASE

 

[TheManiac]

Doubt Chemistry
In question 6(g) how do you know it is manganese?
and yeah the marking scheme is kinda hard to understand sorry about it couldn't find a better one

i will start from beginning of test...
1)T was added to aqueous hydrogen peroxide- splint extinguished (it means that we added something that decompose hydrogen peroxide in oxygen and water... it is catalyst)
2) the gas given off was tasted with glowing splint- splint relight (it is oxygen)
3)Solid T was added to HCl and heated- litmus paper bleached (chlorine gas is produced)
4) and i came to formula...
1&2- 2H2O2 + MnO2 --> 2H2O + O2 + MnO2
3&4- 4HCl + MnO2 --> MnCl2 + 2H2O + Cl2

I hope i helped

 

[Eshmal]

It was really easy nd there was question about pea seed and bean seed .... And potato strips in two different concentration solution