Biology; Chemistry; Physics: Post your doubts here!

[falcon678]

its A. Differential Staining......for details visit this website:
http://en.wikipedia.org/wiki/Differential_staining

 

[VelaneDeBeaute]

Water gains energy to turn into vapours! Doesn't it? So shouldn't it be endothermic?!

And I am a girl everyone! Everyone just assumes I am a guy!

Well from a bond energy point of view, the energy it takes in to break its bonds is less than the total energy it gives out as its bonds are broken ! Therein, it is exothermic !

 

[scouserlfc]

nopes its endothermic go to the individual thread made by RuckingFetard to get explanation

 

[VelaneDeBeaute]

OMG that was so confusing ( Literally i feel like i've never studied this) ! Anyway,
so what we conclude is, this ?
solid--->liquid---->gas = always endothermic because it has to take in energy to break strong bonds in order to form less stable states (thus positive enthalpy)

gas---->liquid---->solid = always exothermic because energy is released as you are forming new, stronger bonds to form the more stable state (thus negative enthalpy)

 

[Minato112]

To find magnification

magnification = length of image \ actaul length

To find length of image

length of image = magnification * actaul length


i hope this helps

THNX A LOOT!

 

[sweetiepie]

ur welcum

 

[risingfast]

Thanx falcon

 

[snowbrood]

Q the survivor of a shipwreck lands on an island which is 300m from a vertical clif he sees a ship anchored between the island and the cliff. a blast from the ship's horn is heard twice with a time lapse of 4s. Calculate the distance d of the ship from the island (Assume that the speed of the sound=330ms).

 

[snowbrood]

can anyone tell me the answer of Jo1 p1 q7 chemistry

 

[scouserlfc]

can u attach the paper if not then wait till tomorrow ill see in my PP book and then ill tell u so just wait,i think in Xtreme papers they dont have the past papers of J 01

 

[awaisbuttrocksCIE]

http://www.xtremepapers.com/CIE/Cambrid ... _qp_22.pdf

B9 part d) i and ii

Need answer with full explanation and working :x

 

[SalmanPakRocks]

^^
d) i)
The balanced equation along with the symbols can easily be made by looking at the Perodic Table!
Pb^+2 (aqueous) + 2I^-1 (aqueous) = PbI^2 (solid) (the symbol here means to state wheather it's solid, liquid, gas or aqueous).

Not sure about part ii

 

[Gémeaux]

d ii) X is a reducing agent as it itself oxidised n reduced manganate ions.. (Mn VII are green so are *reduced* wen they turn orange-brown)

 

[scouserlfc]

yup its a simple redox reaction and both of the above answered it correctly !

 

[SalmanPakRocks]

need some help with Physics Syllabus contents
(d)Describe a simple form of a.c generator (rotating coil or rotating magnet) and the use of slip rings where needed.
(e) sketch a graph of voltage output against time for a simple A.C generator.
(f) describe the structure and principle of operation of a simple iron-cored transformer.
(h)Discuss the environmental and cost implications of underground power transmission compared ot overhead lines.

 

[Gémeaux]

for a.c generator.. refer to Explaining Physics (a book wid blue front cover)
cuz itd b really lengthy xplaining it here

 

[Gémeaux]

hmm.. all of these points r covered in dat buk

 

[SalmanPakRocks]

hmmm ok.

 

[memyself15]

i also used explaining physics for these topics. it clears the concept alot.

 

[SalmanPakRocks]

ok i will try to get that book!