Biology; Chemistry; Physics: Post your doubts here!

[SalmanPakRocks]

whats ethyl ethanoate?...

Ester

 

[Mayedah]

whats ethyl ethanoate?...

Its an ester made from the combination of alcohol ethanol and carboxylic acid ethanoic acid

 

[areexrulz]

imran marchants guess please?..

 

[ashiqbal]

tubes III, IV,V.
Must be Zinc because N displaced Copper but not Magnesium, so it must be less reactive than Mg, but more reactive than Cu.
displacement reaction. fact.
ZnCO3 will decompose to ZnO and CO2

It can also be iron(Fe^2+)

 

[ashiqbal]

One mole of compound X gives three moles of ions in aqueous solution. Sulfuric acidis H2SO4 and one mole of sulfuric acid can give off twoOne mole of compound X gives three moles of ions in aqueous solution. X reacts with ammonium carbonate to give an acidic gas.

What is compound X?

A Calcium Hydroxide
B Ethanoic Acid
C Sodium Hydroxide
D Sulfuric Acid
~~~~~~~~~~~

I know the answer is D. Sulfuric acid. What I would like to know is why.

sulphuric acid gives two H+ ions, and one SO4^2- ion from one mole

 

[haha101]

Didn't get this, mind explaining?

structure mei yeh wala hoga tou hi baney gey acid ! syed1995

 

[Ahmedfj]

help in atp paper june 2008 question 11 .. pls asap !!!!!

 

[ashiqbal]

Hey can anyone tell me,What will happen to the rate of reaction when the VOLUME is increased or decreased.Plz reply fast.

changing volume doesnt effect rate of reaction!

 

[GetSomeLife]

help in atp paper june 2008 question 11 .. pls asap !!!!!

Link please.

Btw, have some doubt on the "test of sulphate"

 

[ashiqbal]

volume and concentration are inversely proportional!!

no! if volume of water is added, only then the concentration would change!! the concentration would not change if HCl is added to HCl!!

 

[Spidey21]

no! if volume of water is added, only then the concentration would change!! the concentration would not change if HCl is added to HCl!!

dude thats simple logic...:|
everyone knows that..:|

 

[ashiqbal]

MASS OF PURE SUBSTANCE/MASS OF TOTAL SAMPLE *100

is your CAPSLOCK stuck dude??

 

[Ahmedfj]

Link please.

Btw, have some doubt on the "test of sulphate"

http://www.xtremepapers.com/papers/...al O Level/Chemistry (5070)/5070_s08_qp_4.pdf

 

[asd]

no! if volume of water is added, only then the concentration would change!! the concentration would not change if HCl is added to HCl!!

LMAO, ure right, stupid mistake i did there.

 

[ashiqbal]

dude thats simple logic...:|
everyone knows that..:|

but increasing volume, eg using 20 cm^3 instead of 10cm^3 of HCl wont change the rate! that is waht they were discussing before ur post!

 

[Vogue]

wat r the catalysts that r used in cracking of hydrocarbons?specially the ones used in the apparatus where there is this tube in which there is a cotton plug soaked in hydrocarbon oil leading to a tube that hv a catalyst nd then ethene is collected abv a water tank in a test tube.

 

[Ahmedfj]

atp paper june 2008 question 3 b i , bii

 

[Spidey21]

Link please.

Btw, have some doubt on the "test of sulphate"

sulphate ions or gas?

 

[Spidey21]

atp paper june 2008 question 3 b i , bii

B(i) hydrogen
(ii)pops and extinguishes a lighted flame

 

[asd]

wat r the catalysts that r used in cracking of hydrocarbons?specially the ones used in the apparatus where there is this tube in which there is a cotton plug soaked in hydrocarbon oil leading to a tube that hv a catalyst nd then ethene is collected abv a water tank in a test tube.

Aluminium Oxide