Enthalpy and hess’ law, Chemistry

Assignment Help:

 

The enthalpy change (ΔH) in a reaction is equal to the heat input under conditions of constant pressure and temperature. It is not equal to the total energy change, as work may be done by expansion against the external pressure. The corrections are usually small, and enthalpy is used as a measure of the energies involved in chemical reactions. Endothermic reactions (positive ΔH) are ones need a heat input, and exothermic reactions (negative ΔH) give a heat output.

Hess' Law states that ΔH does not rely on the pathway taken between initial and final states, and is a consequence of the First Law of Thermodynamics, which asserts the conservation of total energy. It describes a schematic thermodynamic cycle where the ΔH can be expressed as the sum of the values for individual steps:

 

2056_Untitled.png


Related Discussions:- Enthalpy and hess’ law

Please help me, a 5.00 l reaction vessel contains hydrogen at a partial pre...

a 5.00 l reaction vessel contains hydrogen at a partial pressure of 0.588 atm and oxygen gas at a partial pressure of 0.302 atm.Which element is the limiting reactant in the follow

Phenol , Why phenol can also be prepared from chlorobenzene(Dow''s process...

Why phenol can also be prepared from chlorobenzene(Dow''s process)

Sulphur, why does the sulphur has three different valency

why does the sulphur has three different valency

Explain salt bridge with its functions., Salt bridge is a U-shaped tube con...

Salt bridge is a U-shaped tube containing a semi-solid paste of some inert electrolyte like  KCl, KNO 3 , NH 4 Cl,  etc. in agar-agar and gelatin. An inert electrolyte is one which

You, one two three four get on the dance floor..

one two three four get on the dance floor..

The energy for the first excited state of hydrogen atom, The value of the e...

The value of the energy for the first excited state of hydrogen atom will be: (1) - 13.6 ev                        (2)- 3.40 eV        (3) -1.51eV

Atoms, what are atoms made of ?

what are atoms made of ?

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd