Biology; Chemistry; Physics: Post your doubts here!

[scouserlfc]

Look in the books u study or the internet ill look the internet and ill soon post !

 

[sweetiepie]

http://www.google.ae/imgres?q=trachea+s ... ,r:17,s:18

sumthing like this cums for trachea

hope it helps u

 

[VelaneDeBeaute]

can you provide the images of the slides that come in the cie exams ie:
trachea
artery
vein
alveoli
root
stem
leaves
xerophytic leaves with trichomes

It depends ! I don't think there's some specific *website* or source where you can get them from ! There might be but all i can say is memorise/ keep in mind their identifying features e.g. artery's walls are thick and vein's one are thin !! That'll help you to identify the organs !!

 

[Muhammad Talha]

Just read book....n do pst papers as many as u can.....u will r0ck INSHALLAH....

 

[snowbrood]

i read in a book that aluminum will never be discharged. so why do we use electrolysis to extract aluminium
??

 

[Muhammad Talha]

i read in a book that aluminum will never be discharged. so why do we use electrolysis to extract aluminium
??

Ur book has nt described it fully that wat iz the reason behind it.....!!!

 

[lindalinoo]

another question ..
active yeast is placed in a test tube and connected by a delivery tube to a second test tube containing hydrogencarbonate indicator
the color of the indicator was red at the begining but after 15 min's it turns to yellow .. can anyone explain the reason for this change??

i know that hydrogencarbonate is red in neutral, purple in alkaline and yellow in acidic solution .. and yeast is a catalase
how does it change the color of the indicator to yellow?? :unknown:

i'll be glade if i got the answer
my regard

 

[Minato112]

Hi everyone! i need sme help n want sme answers as soon as possible cuz my examss are 2morrow

How do we calculate magnification of a drawing and how do we calculate the total magnification of a drawing if the drawing is re-magnified?

Its Bio ATP

plz help!!!

 

[sweetiepie]

To find magnification

magnification = length of image \ actaul length

To find length of image

length of image = magnification * actaul length


i hope this helps

 

[scouserlfc]

another question ..
active yeast is placed in a test tube and connected by a delivery tube to a second test tube containing hydrogencarbonate indicator
the color of the indicator was red at the begining but after 15 min's it turns to yellow .. can anyone explain the reason for this change??

i know that hydrogencarbonate is red in neutral, purple in alkaline and yellow in acidic solution .. and yeast is a catalase
how does it change the color of the indicator to yellow?? :unknown:

i'll be glade if i got the answer
my regard

Easyyyyy
u shud know that CO2 is acidic and in respiration of yeast it gives out CO2 so it will turn hydrogen carbonate yellow simple !

 

[sweet fairy]

Formation of water vapour from water

and reacting hydrogen and oxygen together.

Are these endothermic or exothermic reactions?

 

[VelaneDeBeaute]

Endothermic i guess!

 

[sweet fairy]

Endothermic i guess!

How so? Wouldn't heat be needed by to convert water into water vapour???? So wouldn't it be an endothermic reaction?

 

[SalmanPakRocks]

I think Exothermic Reation but I will surely conform it! Weak in Chem and physics due to accounts!

 

[VelaneDeBeaute]

MY REPLY ! YE TOH ADHA HAI ! I typed and all the rest of bakwaas is nowhere ! God, AMAZING ! :x
Alright so water loses energy to surrounding and evaporates as water vapours. Exothermic then !

 

[VelaneDeBeaute]

Other one is exothermic is well ! sorry man, mistakes occur !

 

[sweet fairy]

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!

 

[lindalinoo]

Easyyyyy
u shud know that CO2 is acidic and in respiration of yeast it gives out CO2 so it will turn hydrogen carbonate yellow simple !

oh thats what i wanted to make sureee .. thanks
what about if a plant were placed in a test tube containing hydrogen carbonate??
plant will release oxygyen isn't it .. so is oxygen also acidic??
what if plant + small animals such as snails were placed in the same tube?

 

[scouserlfc]

Weell no oxygen is slightly basic so both co2 and oxygen in a container will neutralize each other.

Now for the reactions whether they are exotic or endorsement both reactions are exothermic if u want explanation just ask!

 

[risingfast]

Chromatography is one of several separation techniques. Which of the following terms is closely related with chromatography in terms of working?


A. Differential staining
B. Centrifugation
C. Spectrophotometry
D. Electrophoresis