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

Place light rays from largest to smallest wavelength, Q. Place these types ...

Q. Place these types of light in order from largest to smallest wavelength. Blue light, x-rays, gamma rays, microwaves, green light? Largest wavelength microwaves green l

Citrate synthase, how is the regulation of citrate synthase?

how is the regulation of citrate synthase?

Why nh3+ does not form complex compounds, IN AMMONIUM ION NITROGEN DOESNT H...

IN AMMONIUM ION NITROGEN DOESNT HAVE VALENCE ELECTRONS IN ITS VALENCE ORBITAL.

The reversible hydration of carbon dioxide, The reversible hydration of car...

The reversible hydration of carbon dioxide The reversible hydration of carbon dioxide to carbonic acid is an acid-catalyzed addition of water that is mechanistically identical

What are natural or synthetic food colours?, Q. What are natural or synthet...

Q. What are natural or synthetic food colours? Food in raw state has a natural colour, which is associated with the characteristics of that food. In the processing, preservatio

Determine wavelength of the radiation emitted, The wavelength of the radiat...

The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant 1.097 x 10 7 m -1 ) (1) 406 nm

The number of unpaired electrons in an o2 molecule, The number of unpaired...

The number of unpaired electrons in an O 2   molecule is: (1) 0        (2) 1         (3) 2      (4) 3 Ans: 2

Does ph affect the enzyme activity, The concentration of hydrogen ions in s...

The concentration of hydrogen ions in solution affects the enzyme activity. Every enzyme has maximal efficiency under an optimum pH. As pH is one of the factors for the denatura

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