Physics, Chemistry and Biology: Post your doubts here!

[Usman Abdul Jabbar]

no i only need it only for the exam only

i mean like only temporary not extra functions

 

[Awesome12]

i mean like only temporary not extra functions

yeah alright whatever suits u
i was just saying so, so that u cud have a permanent one instead of constantly buying new calculators

 

[Omar alnajjar]

Physics IGCSE QUESTION: DESCRIBE IN TERMS OF ITS ATOM (SPOON) HOW THERMAL ENERGY TRANSFERRED THROUGH A METAL?

 

[asimkhanfar]

can anyone give me some online sources for bio/physics/chem besides the bbc bitesize? I want something with extra details, not just a summary of the chapter.

thanks

 

[Awesome12]

Physics IGCSE QUESTION: DESCRIBE IN TERMS OF ITS ATOM (SPOON) HOW THERMAL ENERGY TRANSFERRED THROUGH A METAL?

heat energy is absorbed by the free electrons and they pass on the heat to each other

 

[kirann]

Describe the processes by which energy is converted from one form to another,including refernce to
(1) chemical/feul energy (a re-grouping of atoms)
(2) hydroelelctric generation ( emphasising the mechanical energies involved)
(3) solar energy (nuclei of atoms in the sun)
(4) nuclear energy
(5) geothermal energy
(6) wid energy
Plz help
Can anybody explain?

 

[shoaib672002]

need answer fast
View attachment 36935

View attachment 36937

I am pretty sure the question says LAMPS and as far as i know lamp has a symbol

 

[Awesome12]

I am pretty sure the question says LAMPS and as far as i know lamp has a symbol

yup ur right
my bad
i was solving another question for someone else and i think i mixed it up with this part

 

[princess sofia]

my chem book says dat in extraction of iron from its ore
CaCO3 == CaO + CO2 by decomposition
but carbonates of calcium donot decompose ??

 

[Awesome12]

my chem book says dat in extraction of iron from its ore
CaCO3 == CaO + CO2 by decomposition
but carbonates of calcium donot decompose ??

No Carbonates of Ca do decompose, infact all the carbonates of metals from Ca to Cu in the reactivity series decompose to form the metal-oxide and CO2

 

[princess sofia]

What is the structure of hydrazine
Is there a double bond or single bond between nitrogen atoms

 

[princess sofia]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s05_qp_3.pdf
plz help !!!
q4 part d
cn get how would we fnd value of x
thnx in advance

 

[Phoenix Blood]

Why does a plant grown from a seed not identical to it's parent?

 

[Phoenix Blood]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Chemistry (0620)/0620_s05_qp_3.pdf
plz help !!!
q4 part d
cn get how would we fnd value of x
thnx in advance

I think x=2.
The percentage of the water is it's mass.
So find the number of moles, using the formula, moles= mass/Mr
You will get 0.58 for cas04 and 1.16 for h2o
so the ratio is 1:2
so x=2
Hope this helps

 

[Phoenix Blood]

Why does pesticide accumulate more in an organism as the trophic level increases? It should decrease, right? Because some will be lost in excretion,respiration and all...

 

[Phoenix Blood]

I don't think we have to know such minute details for our MayJune IGCSE...do we?

What is the structure of hydrazine
Is there a double bond or single bond between nitrogen atoms

 

[Awesome12]

Why does pesticide accumulate more in an organism as the trophic level increases? It should decrease, right? Because some will be lost in excretion,respiration and all...

As time goes by, the harmful effects of the pesticides affect may parts of the body. When another organism feeds on it, it also gets it and it develops in its body ...
Energy decreases as the trophic level increases

 

[princess sofia]

I don't think we have to know such minute details for our MayJune IGCSE...do we?

they had asked it in a past paper i guess of 2004

 

[princess sofia]

I think x=2.
The percentage of the water is it's mass.
So find the number of moles, using the formula, moles= mass/Mr
You will get 0.58 for cas04 and 1.16 for h2o
so the ratio is 1:2
so x=2
Hope this helps

thanx alot thx chem is driving me crazy

 

[princess sofia]

Why does pesticide accumulate more in an organism as the trophic level increases? It should decrease, right? Because some will be lost in excretion,respiration and all...

the more the trophic level increases , the bio mass decreases n in other words it become more concentrated
like if a catterpillar has suppose 0.02 mg of pesticide in it , each bird feeds on many catterpillars so the concentration in its body is more than it is in the body of da catterpillar
hope thx helps