Biology; Chemistry; Physics: Post your doubts here!

[Mayedah]

Oh another one, for how many decimal places we have to calculate the empirical formula?

wasn't the emperical formulae in whole no's ??

Yes its always in whole numbers if not thn we have to multilpy both with a number so it gives a whole number !

 

[a.abid]

D is the only possible answer to it !

why not B?

 

[malay]

If anyone here is having the pastpapers book,cud u plz explain what is the answer for June 2000 PAper 1 Mcq....part 3

D coz da 2nd spot frm da green ink travelled da same distance as da spot in da yellow ink

 

[Mayedah]

Its not B because if u luk deeply into it its not on the same line ...red die is a little lower thn blue !

 

[bogus]

Guys... I canr remember which mcq paper it was but there was this paper where a reaction occurs (decomposition of H2O2 i guess) where the first few test tubes were rejected because they contain nitrogen. Can u explain it to me and potst the question if u can find it? Thanks in advance

 

[syed1995]

why not B?

Red ko ghaur say dekho ooper walay dot ko .. thora sa neechay hai brown kay dot kay ..

 

[a.abid]

Its not B because if u luk deeply into it its not on the same line ...red die is a little lower thn blue !

D coz da 2nd spot frm da green ink travelled da same distance as da spot in da yellow ink

thanks alot it helped

 

[syed1995]

Guys... I canr remember which mcq paper it was but there was this paper where a reaction occurs (decomposition of H2O2 i guess) where the first few test tubes were rejected because they contain nitrogen. Can u explain it to me and potst the question if u can find it? Thanks in advance

2 Pages back we discussed it!!!

http://www.xtremepapers.com/papers/...al O Level/Chemistry (5070)/5070_s08_qp_1.pdf
MCQ 1

Answer

jee nitrogen hai first few will be contaminated by air so ans is nitrogen

 

[malay]

thanks alot it helped

no prob.

 

[Mayedah]

Guys... I canr remember which mcq paper it was but there was this paper where a reaction occurs (decomposition of H2O2 i guess) where the first few test tubes were rejected because they contain nitrogen. Can u explain it to me and potst the question if u can find it? Thanks in advance

June 2008 paper 1 mcq no 1

 

[SomeStudent]

Yes its always in whole numbers if not thn we have to multilpy both with a number so it gives a whole number !

e.g divide the percentage by say, 12 55.8/12 will i write the next step as 4.6 4.65?

 

[a.abid]

Red ko ghaur say dekho ooper walay dot ko .. thora sa neechay hai brown kay dot kay ..

yes thanks

 

[bogus]

2 Pages back we discussed it!!!

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Chemistry (5070)/5070_s08_qp_1.pdf
MCQ 1

Answer

why not water vapor?

 

[Mayedah]

thanks alot it helped

Anytime

 

[Mayedah]

why not water vapor?

Its nitrogen because nitrogen is mostly present in air in higher concentration !

 

[syed1995]

e.g divide the percentage by say, 12 55.8/12 will i write the next step as 4.6 4.65?

If the percentages are coming

Ca50/12 X20/6

that becomes

Ca4.2 X3.33

then divide both with 3.33

Ca4.2/3.3 X3.33/3.33

Ca1.26X1

which becomes

CaX

 

[Mayedah]

e.g divide the percentage by say, 12 55.8/12 will i write the next step as 4.6 4.65?

4.65 ...dnt round off till the end !

 

[malay]

Guys... I canr remember which mcq paper it was but there was this paper where a reaction occurs (decomposition of H2O2 i guess) where the first few test tubes were rejected because they contain nitrogen. Can u explain it to me and potst the question if u can find it? Thanks in advance

ywr is mein confusion kia ha 1st few tubes r rejected coz the nitrogen in air results in contamination...simple

 

[bogus]

Its nitrogen because nitrogen is mostly present in air in higher concentration !

ok i have a feeling we'll get it tomorrow !

 

[syed1995]

why not water vapor?

water vapour won't get collected in the tube... isn't water soluble in water ? it will get mixed with other gases!