Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  2
Author: Subject: Water production during combustion and its effect on heat ????
DraconicAcid
International Hazard
*****




Posts: 3950
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Online

Mood: Semi-victorious.

[*] posted on 7-5-2013 at 14:50


Quote: Originally posted by KonkreteRocketry  
Ok cool,

I cant find any enthalpy of Cl = O bonds, so then i found Chlorine dioxide on wikipedia which is O=Cl=O says the enthalpy is 104.60, so can i assume Cl = O is half of 104.60 ?

No, that's the enthalpy of formation, not a bond enthalpy.




Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
View user's profile View All Posts By User
KonkreteRocketry
Hazard to Others
***




Posts: 165
Registered: 12-11-2012
Location: Dubai
Member Is Offline

Mood: No Mood

[*] posted on 7-5-2013 at 15:14


Quote: Originally posted by DraconicAcid  
Quote: Originally posted by KonkreteRocketry  
Ok cool,

I cant find any enthalpy of Cl = O bonds, so then i found Chlorine dioxide on wikipedia which is O=Cl=O says the enthalpy is 104.60, so can i assume Cl = O is half of 104.60 ?

No, that's the enthalpy of formation, not a bond enthalpy.


but if i know they got the enthalpy from Cl2 + O2 i can still work out the C=O energy right ?
View user's profile View All Posts By User
DraconicAcid
International Hazard
*****




Posts: 3950
Registered: 1-2-2013
Location: The tiniest college campus ever....
Member Is Online

Mood: Semi-victorious.

[*] posted on 7-5-2013 at 15:21


Quote: Originally posted by KonkreteRocketry  
Quote: Originally posted by DraconicAcid  
Quote: Originally posted by KonkreteRocketry  
Ok cool,

I cant find any enthalpy of Cl = O bonds, so then i found Chlorine dioxide on wikipedia which is O=Cl=O says the enthalpy is 104.60, so can i assume Cl = O is half of 104.60 ?

No, that's the enthalpy of formation, not a bond enthalpy.


but if i know they got the enthalpy from Cl2 + O2 i can still work out the C=O energy right ?

You can work it out. Show your calculations, and I'll tell you if you're on the right track.




Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
View user's profile View All Posts By User
Ral123
International Hazard
*****




Posts: 735
Registered: 31-12-2011
Member Is Offline

Mood: No Mood

[*] posted on 7-5-2013 at 21:39


Don't work it out. Use wikipedia, youtube and people's opinion about propellant performance.
View user's profile View All Posts By User
Dornier 335A
Hazard to Others
***




Posts: 229
Registered: 10-5-2013
Location: Northern Europe
Member Is Offline

Mood: No Mood

[*] posted on 10-5-2013 at 12:38


You don't have to care about the enthalpy of single bonds inside the molecule. The enthalpy of formation is easy to find for many compounds.
Neither is all the steps in the reaction relevant. All you have to know is the reactants' ΔHf and the products' ΔHf.
The enthalpy change of reaction is the sum of ΔH for the products minus the sum of ΔH for the reactant(s).

The decomposition of NH4ClO4
2 NH4ClO4(s) → Cl2(g) + N2(g) + 2 O2(g) + 4 H2O(g)
(1*0 + 1*0 + 2*0 + 4*-241.8)-(2*-295.3)

The ΔH of this reaction is -380.6 kJ/mol so it is exothermic. And yes, it is the water produced in the reaction that liberates this energy.
View user's profile Visit user's homepage View All Posts By User
 Pages:  1  2

  Go To Top