Physics, Chemistry and Biology: Post your doubts here!

[AAnsarii]

are steel and graphite both good conductors of electricity???
is wood a fossil fuel or just a fuel??
someone plz answer soon!!

yes steel n graphite r both gud whatever
wood isnt a fossil fuel, they r really old remains of ancient organisms

 

[FATIMAH]

plz explain me this question : )

 

[EpicLol]

plz explain me this question : )View attachment 12782

when u draw the whole molecule, there are 17 pairs of bonds(1 pair = 1 line) so yeah u add them up and they add up to 17

 

[FATIMAH]

26) C- remember that you have to remove one of the parts of the fire triangle (heat, fuel, oxygen)
22) C- sodium hydroxide gives white pt with Zn, silver nitrate gives white ppt with chlorides.
23) A- the concentration of the acid decreases.
17) A. (I just remember the answer, you didn't give the substances in bold)

any idea that q 26 is from which year Student of the year

 

[FATIMAH]

when u draw the whole molecule, there are 17 pairs of bonds(1 pair = 1 line) so yeah u add them up and they add up to 17

thanks alot

 

[Z.A.M]

how was the Bio P1 V1

 

[white rose]

when u draw the whole molecule, there are 17 pairs of bonds(1 pair = 1 line) so yeah u add them up and they add up to 17

but i m getting as 14???

 

[white rose]

a wanna ask 1 ques. abt chem....
if we add water to any acid does pH changes??? thanx

 

[EpicLol]

a wanna ask 1 ques. abt chem....
if we add water to any acid does pH changes??? thanx

dilute acid so I think it does but Im not so sure....

 

[thats_me]

but i m getting as 14???

Count the bonds for CH3 CH2 also ..

 

[thats_me]

a wanna ask 1 ques. abt chem....
if we add water to any acid does pH changes??? thanx

Yes the pH increases but it doesnot become alkaline..

 

[Student of the year]

THANKS GUYS FOR THE HELP
BUT HOW IS THE ANS FOR Q17 A.
the bold words are :
A-wax
B-hydrogen chloride
C-carbon dioxide
D-sodium hydroxide

 

[Maz]

dilute acid so I think it does but Im not so sure....

a wanna ask 1 ques. abt chem....
if we add water to any acid does pH changes??? thanx

No, the pH of the acid doesn't change, only the concentration changes.

 

[Lost_Life]

but i m getting as 14???

you are only counting the lines given y the drawing,write or draw the whole molecule then count the pairs of electrons

 

[white rose]

Count the bonds for CH3 CH2 also ..

oh yeah...i got it...thanks

 

[Maz]

Yes the pH increases but it doesnot become alkaline..

Are you sure?
Conc.HCl , dil.HCl , both have the same pH of 1.

 

[Lost_Life]

THANKS GUYS FOR THE HELP
BUT HOW IS THE ANS FOR Q17 A.
the bold words are :
A-wax
B-hydrogen chloride
C-carbon dioxide
D-sodium hydroxide

i think its wax??? i did the question a while ago,but dont remember it..

 

[Lost_Life]

QUESTION !!
MJ 11 VARIANT 12..
NUMBER 3 WHY IS C NOT B :S PLEASE HELP :'(
http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s11_ms_12.pdf

 

[EpicLol]

Are you sure?
Conc.HCl , dil.HCl , both have the same pH of 1.

http://wiki.answers.com/Q/Does_adding_water_change_the_pH_of_an_acid
Yea it does increase

 

[white rose]

No, the pH of the acid doesn't change, only the concentration changes.

are u SURE abt dat ans.....