how was chemistry p21?????!!!

[robinho10]

plz tell me the questions!

 

[wonderland]

what was the answer for last question the one with 6 marks i got +60 kjmol-1 .however many of my of friend got something +225 what was the answer.
the way i did was as is to find the enthapy of formation.........
2H2 + 2C --> C2H2
Product - reactants
s0 (-1300)-(2(-288) + 2(392)) = +60kjmol-1

 

[libra94]

@wonderland its reactants - products
my mistake in this ques was that i balanced the equation in such way that C2H2 had 2 moles instead of 1!!
and what abt the reagants and conditions of coverting halogenoalkanes to alkynes (triple bond)??

 

[wonderland]

I THINK IT WAS DILUTE H2SO4 AND CONIDITION HEAT UNDER REFLUX WAS IT RIGHT libra94 .WHAT DID U WRITE

 

[wonderland]

what was the equation for the C2H5SH +O2 ---> S02 + CO + CO2 WAS IT
I DIDNT TAKE WATER SINCE WHAT COULD HAVE BEEN THE CAUSE OF POLLUTION FOR H20 --- libra94

 

[libra94]

there was water cuz they told us that oxide of different elements were formed!!
and then they asked that ONLY 2 OF THE OXIDES ARE DANGEROUS TO THE ENVIRONMENT which was SO2 and CO2

 

[libra94]

why H2SO4 nad reflux??
it was an elimination reaction.

 

[wonderland]

I AM NOT SURE WHAT DID U WRITE

 

[libra94]

well ehmm
m not sure too
i wrote pumice and heat , cuz we use this in an elimination reaction :S

 

[ibrahimovais]

It was a very easy paper.....for enthalpy change the answere was 226kj....for the number of moles was 273tonnes...the organic was very easy..alhamdullelah

 

[wonderland]

HEY I REMEMBER THAT THEY TOLD TO WRITE ABOUT 3 OXIDE CAUSING POLLUTION .FUTHERMORE IT WAS 3 MARKS libra94

 

[libra94]

yeah it was easy, but what did u write for the reagants and conditions for converting halogenoalkanes to alkynes????

 

[wonderland]

ibrahimovais HOW IT WAS +226KJMOL-1.

 

[libra94]

noo, they asked for 2 :/
they asked for the harmful effects and how it effects the environment, or something like that which makes 3 marks

 

[wonderland]

HOW MANY MARK WAS THE EQUATION FOR libra94

 

[wonderland]

libra94 WHAT WAS THE ANSWER FOR THE OBSERVATION FOR CAL(OH)2 FOR CALCIUM AND CALICIUM OXIDE SOMETHING

 

[libra94]

i dont remeber, maybe 1 or 2
and yeahhhh, one more ques, what is the other reagant u use to get Z other than using dilute sulphuric acid????

 

[libra94]

i wrote that for Ca dissloves in the first one and CaO does not dissolve in the second one!
what did u write?

 

[wonderland]

I WROTE THAT WHITE SOLID FORMS FOR CA(OH)2 FOR BOTH OF THEM ...
AND FOR THE SULPHURIC ACID ONE I WROTE H2SO3(SULPHUROUS ACID)

 

[wonderland]

WHAT WAS THE ANSWER FOR OUTLINE HOW CRACKING TAKE PLACE ...
I WROTE HIGHER TEMPERATURE ,PRESSURE AND USING CATALYST............
WAS IT RIGHT