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

p-methoxybenzyl bromide reacts with ethanol, Why does p-methoxybenzyl brom...

Why does p-methoxybenzyl bromide reacts with ethanol faster than p-nitrobenzylbromide Solution) Because o-ch 3 is electron donating group while NO 2 is a electron withdrawing g

Will benzylic halide undergo sn1 or sn2 mechanism?why?, Benzylic halide fol...

Benzylic halide follows sn1 mechanism always...............the order of halides going sn1 rxn is BENZYL>ALLYL>TERTIARY>SECONDARY>PRIMARY>METHYL beacause of stability, benzyl & ally

Transport number, how to calculate transport number by moving boundary meth...

how to calculate transport number by moving boundary method

Atoms, what are atoms made of ?

what are atoms made of ?

Titration of hcl with standard sodium carbonate solution, how do you calcul...

how do you calculate the concentration of hcl solution if you are the mass of sodium carbonate and the volume of its solution and the volume of the pipetted solution and the volume

Fe atomic number = 26 atom has the electronic arrangement, Fe(atomic number...

Fe(atomic number = 26) atom has the electronic arrangement: (1) 2, 8,  8, 8         (2) 2, 8, 16        (3) 2, 8,14, 2             (4) 2, 8, 12, 4 Ans:  2, 8,14, 2

Which statement is not correc, Which statement is not correct for n=5, m=3:...

Which statement is not correct for n=5, m=3: (1) l=4                    (2) l=0, 1.3, s =+1/2            (3) l= 3                  (4) All are correct Ans:l=4

Nomenclature of simple aromatic compounds, Nomenclature of simple aromatic ...

Nomenclature of simple aromatic compounds Aromatic compounds are those that consist of one or more benzene rings in them. An aromatic substance has two major types: (1) Nucl

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