Register to reply

Is Delta H of formation the same for NH4NO3 Aqueous and in Solid Form?

by Austin
Tags: aqueous, delta, formation, nh4no3, solid
Share this thread:
Austin
#1
May8-14, 12:05 AM
P: 10
I am doing a project in Chemistry and I need to use Hess' Law to cancel two equations and if in one equation the NH4NO3 is solid and in the second one the NH4NO3 is aqueous.

The equations are:
1: NH4NO3 (s) + HCl (aq) --> HNO3 (aq) + NH4Cl (aq)
2: NH4OH (s) + HNO3 (aq) --> H2O (l) + NH4NO3 (aq)

I will find the heat of reaction for both of these reactions and use those values and Hess' law to find the Delta H of this reaction:

HCl (aq) + NH4OH (s) --> NH4Cl (aq) + H2O (l)


I am wondering if these procedure will work because I created this myself for the project we are doing and I don't know:

1. Whether these individual reactions work
2. Whether they add up to the overall reaction and whether that reaction even works.

The part that is getting me stuck up is whether I can use Hess' law to cancel and aqueous version of NH4NO3 with a solid version.

Your knowledge and advice is much appreciated!
Thank you!
Phys.Org News Partner Chemistry news on Phys.org
Chemists create nanofibers using unprecedented new method
Nanostructured metal-oxide catalyst efficiently converts CO2 to methanol (w/ Video)
Researchers discover low-grade nonwoven cotton picks up 50 times own weight of oil
DrClaude
#2
May8-14, 02:29 AM
Sci Advisor
PF Gold
DrClaude's Avatar
P: 1,325
You have to take into account the enthalpy of solution. The Wikipedia entry http://en.wikipedia.org/wiki/Enthalp...ge_of_solution lists a few values, including that for ammonium nitrate.

[Edit: I don't know why I focussed on ammonium nitrate, which is not what you asked about. See Borek's much better answer.]
Borek
#3
May8-14, 02:39 AM
Admin
Borek's Avatar
P: 23,400
No such thing as solid NH4OH.


Register to reply

Related Discussions
Kronecker Delta and vector form of q_(i,j) q_(m,mj) Calculus 0
Negative formation energy of a point defect in a solid Atomic, Solid State, Comp. Physics 1
Delta H of formation for diatomic molecules. Chemistry 5
How many moles of NH3 in the supplied solution0.2 M NH3 in 2 M Nh4NO3 Biology, Chemistry & Other Homework 1
Delta Heat of Formation Chemistry 2