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ALL CIE CHEMISTRY DOUBTS HERE !!
tmisterr:
using the mole ratio, x mole of HI will produce 0.5 mole of H2 and 0.5 mole of I2 so so at equilibrium there will be b-x mole of HI remaining.
Now Calculate the partial pressures gas, in total we have b-x+0.5x+0.5x which is b moles of gases. partial pressure HI is therefore b-x/b for H2 is 0.5x/b and for I2 it is again 0.5x/b.
Replace these values into the Kp equation = p[H2]*p[I2]/p[HI]2
we get (0.5xp/b)2/((b-x)p/b)2
from here it is just simple simplification, the p2 and b2 will cancel out top and bottom and in the end you get 0.25x2/(b-x)2 which is = x2/4(b-x)2
elemis:
+rep tmisterr
Thanks ;)
elemis:
http://www.freeexampapers.com/download.php?l=A%20Level/Chemistry/CIE/2002%20Nov/9701_w02_qp_1.pdf&t1=2wypmop&t2=31e3abol
Question 17.
For Question 36 Ammonia is a reducing agent because it loses Hydrogen, correct ?
Deadly_king:
--- Quote from: Kirin on December 07, 2010, 09:39:08 am ---http://www.freeexampapers.com/download.php?l=A%20Level/Chemistry/CIE/2002%20Nov/9701_w02_qp_1.pdf&t1=2wypmop&t2=31e3abol
Question 17.
For Question 36 Ammonia is a reducing agent because it loses Hydrogen, correct ?
--- End quote ---
Nov 02 p1
17. In this question, all the four answers sounds good from the first view. But there's once best and we need to find out which one.
The question is asking about the enthalpy change of formation, that is the energy required when HCl is formed from its reactants at rtp or it could also be the reverse, that is the conversion of HCl to its reactants.
For this we just need to break the C-Cl bond and H-I bond.
Electronegativity does not affect enthalpy changes. Activation energy will not be the reason since it's only the energy required for the reaction to start. Since we're doing the reverse bond energy of the halogens is not required.
I'll take only HCl for explanation. Same principle is applied for HI.
Option C refers to the energy required to break the bond between Hydrogen and the chlorine atom, that H-Cl . Upon breaking this bonds we obtain the atoms of hydrogen and chlorine which will combine together to form hydrogen gas and chlorine molecule.
In other words we have converted H-Cl to H2 and Cl2 and the energy required to do so is the same as the enthalpy change of formation of the molecule except for the sign which will be opposite. This is we're converting H-Cl to H2 and Cl2 while enthalpy change of formation is the conversion of Cl2 and H2 to HCl.
Bond energy for H-Cl is greater since Cl is a smaller atom, hence force of attraction will be greater. ;)
So answer is C.
36. You're right. ;)
elemis:
Dude, the answer is 17 C.
Anyways, how is it C ? What does option C even mean ?
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